Predicate Devices

Reference Devices

Not Found

AI/ML (Artificial Intelligence / Machine Learning)

No
The summary describes a system based on microfluidic sensors and resonant frequency measurements to determine organism concentration and mass distribution for AST. The interpretation of results is based on FDA-defined or recognized breakpoints. There is no mention of AI or ML in the device description, intended use, or performance studies.

Therapeutic

No.
This device is an in vitro diagnostic (IVD) test used for antimicrobial susceptibility testing, which provides information about how effective an antibiotic might be against a bacterial infection. It does not directly treat or cure any medical condition.

Diagnostic

Yes

The "Intended Use / Indications for Use" section explicitly states that "The LifeScale AST system is a multiplexed in vitro diagnostic test." It also indicates that the system provides "Interpretive results (Susceptible/Intermediate/Susceptible-dose dependent/Resistant) for specific drug/organism combinations," which are intended to be "used in conjunction with other clinical and laboratory findings," indicating its role in diagnosis and treatment decisions.

SaMD (Software as a Medical Device)

No

The device description explicitly states it is a "semi-automated instrument system" and uses a "microfluidic sensor," indicating the presence of hardware components beyond just software.

IVD (In Vitro Diagnostic)

Yes, this device is an IVD (In Vitro Diagnostic).

Here's why:

Intended Use: The "Intended Use / Indications for Use" section explicitly states that the LifeScale AST system is a "multiplexed in vitro diagnostic test". It also describes its use for "quantitative antimicrobial susceptibility testing (AST)" performed "directly on blood cultures". This clearly indicates the device is intended for testing samples taken from the human body (blood) outside of the body (in vitro) to provide information for diagnosis and treatment decisions (antimicrobial susceptibility).
Device Description: The "Device Description" further reinforces this by describing the system as a "semi-automated instrument system for antimicrobial susceptibility testing (AST) directly from positive blood cultures". It explains how it measures bacterial characteristics to determine MIC values and interpretive results (susceptible, intermediate, or resistant), which are used in clinical decision-making.
Performance Studies: The detailed descriptions of performance studies, including comparison to a reference method (Broth Microdilution), reproducibility, sample stability, inoculum density, media equivalence, and interfering substances, are all typical evaluations performed for IVD devices to demonstrate their analytical and clinical performance.
Predicate Device: The mention of a "Predicate Device(s)" (K211815 LifeScale™ Gram Negative Kit (LSGN) with the LifeScale AST system) indicates that this device is being compared to a previously cleared IVD device, which is a common regulatory pathway for IVDs.

All of these elements strongly support the classification of this device as an In Vitro Diagnostic.

PCCP (Predetermined Change Control Plan) Authorized

Yes
The letter explicitly states, "FDA's substantial equivalence determination also included the review and clearance of your Predetermined Change Control Plan (PCCP)."

Overview

Intended Use / Indications for Use

The LifeScale AST system is a multiplexed in vitro diagnostic test that uses a microfluidic sensor and resonant frequency to calculate organism concentration and/or mass distribution for quantitative antimicrobial susceptibility testing (AST). Testing is performed directly on blood cultures signaled as positive by a continuous monitoring blood culture system and confirmed by Gram stain. The LifeScale AST system does not provide organism identification and is not indicated for use with polymicrobial samples. Interpretive results (Susceptible/Intermediate/Susceptible-dose dependent/Resistant) are provided for specific drug/organism combinations. Results are intended to be used in conjunction with other clinical and laboratory findings. Standard laboratory protocols for processing positive blood cultures should be followed to ensure availability of isolates for supplemental testing as needed. Additionally, subculture of positive blood culture is necessary for the susceptibility testing of organisms present in polymicrobial samples, for testing antimicrobial agents and species not indicated for testing with the device and for epidemiologic testing and for recovery of organisms present in microbial samples.

The LifeScale Gram Negative Kit (LSGN) is intended for use with the LifeScale AST system for in vitro testing of positive blood culture samples confirmed by Gram stain as containing gram-negative bacilli for the antimicrobial agents and specific target organisms identified below:

Ampicillin: Escherichia coli
Aztreonam: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca
Cefazolin: Escherichia coli, Klebsiella pneumoniae, Klebsiella variicola
Ceftazidime: Acinetobacter spp. (other than Acinetobacter ursingii), Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Klebsiella pneumoniae, Pseudomonas aeruginosa
Ertapenem: Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Klebsiella oxytoca
Trimethoprim-Sulfamethoxazole: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, 6. Klebsiella variicola
Amikacin: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruqinosa
Cefepime: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa
Ceftazidime-avibactam: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca
Gentamicin: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruginosa
Levofloxacin: Escherichia coli, Klebsiella pneumoniae, Klebsiella derogenes, Klebsiella oxytoca, Pseudomonas aeruginosa
Meropenem: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa
Meropenem-vaborbactam: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca
Piperacillin-tazobactam: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa

Product codes (comma separated list FDA assigned to the subject device)

SAN, LON

Device Description

The Affinity Biosensors LifeScale Gram Negative Kit (LSGN) is a semi-automated instrument system for antimicrobial susceptibility testing (AST) directly from positive blood cultures for which the Gram stain shows gram-negative bacilli. The system uses a microfluidic sensor that detects organisms in suspension and measures differences in cell mass between bacterial suspensions incubated in the presence and absence of antibiotic. Minimum inhibitory concentrations (MICs) are determined from data obtained during sample measurement including organism concentration and/or cell mass distributions of individual organisms. The system automatically interprets the measurements to determine MIC values and interpretive results (susceptible, intermediate, or resistant) based on FDA-defined or recognized breakpoints. The organism identification determined using a platform FDA-cleared for use with positive blood culture samples is entered by the user. If the organism identification has not been entered or if the sample has not been confirmed as monomicrobial, the system provides a preliminary report that indicates that organism identification or monomicrobial status is pending. The device Instructions for Use indicates that the preliminary laboratory report should not be reported to the healthcare provider. The final report is provided to the healthcare provider when the organism identification is entered into the system and the culture is confirmed to be monomicrobial samples should not be tested with the LifeScale LSGN Kit. Preliminary results are available in most cases within four hours from initiation of the assay.

Mentions image processing

Not Found

Mentions AI, DNN, or ML

Not Found

Input Imaging Modality

Not Found

Anatomical Site

Not Found

Indicated Patient Age Range

Not Found

Intended User / Care Setting

Laboratory

Description of the training set, sample size, data source, and annotation protocol

Not Found

Description of the test set, sample size, data source, and annotation protocol

Not Found

Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)

Comparison Study:
The study compared the performance of the LifeScale Gram Negative Kit (LSGN) with the LifeScale AST system against the reference Broth Microdilution (BMD) method.
Sample Size: Not explicitly stated, but includes prospective clinical blood cultures (PBCs) and contrived blood cultures. For the exclusion data, 6164 tests were initiated.
Key Results:
Out of 6164 tests initiated, 97.62% (6017/6164) yielded results. The total percentage of excluded or incomplete tests was 2.38%.
Performance was evaluated based on Essential Agreement (EA), Category Agreement (CA), Very Major Discrepancy (VMJ), Major Discrepancy (MAJ), Minor Discrepancy (MIN), and Growth Failure Rate.
For drug/organism combinations, performance metrics like EA and CA were provided. For example, Amikacin-Acinetobacter spp. showed 100.0% EA and 97.4% CA. Cefepime-Pseudomonas aeruginosa showed 93.1% EA and 84.2% CA with 10.34% VMJ. Limitations were proposed for certain drug/organism combinations due to high discrepancy rates (e.g., Cefepime for P. aeruginosa when MIC is 4 µg/mL, and Meropenem for K. oxytoca when LifeScale MIC is 0.5 µg/mL).
Several limitations from the K211815 submission were removed based on additional clinical evaluation testing for Aztreonam, Ceftazidime, Ertapenem, and Cefazolin, indicating acceptable performance after combined data review.

Analytical Performance Data:
Reproducibility Study:
Sample Size: Not explicitly stated for the overall study, but includes 481 tests for Amikacin, 509 for Cefepime, 350 for Ceftazidime-avibactam, 509 for Gentamicin, 373 for Levofloxacin, 534 for Meropenem, 287 for Meropenem-vaborbactam, and 566 for Piperacillin-tazobactam.
Key Results: Best-case and worst-case reproducibility were found acceptable for all antibiotics tested (Amikacin, Cefepime, Ceftazidime-avibactam, Gentamicin, Levofloxacin, Meropenem-vaborbactam, and Piperacillin-tazobactam), with worst-case reproducibility consistently above 89%. Inter-site reproducibility data was also acceptable.

Sample Stability Study:
Sample Size: 13 samples for Amikacin, Meropenem, and Piperacillin-tazobactam. 11 samples for Cefepime, Ceftazidime-avibactam, Gentamicin, and Levofloxacin. 9 samples for Meropenem-vaborbactam. Total 92 samples.
Key Results: Sample stability was assessed at 13 hours post-positivity (T13) compared to T0. Overall EA was 96.00% (264/275). Amikacin, Meropenem, and Meropenem-vaborbactam showed EA

Regulation Number and Section

§ 866.1650 A cellular analysis system for multiplexed antimicrobial susceptibility testing.

(a)
Identification. A cellular analysis system for multiplexed antimicrobial susceptibility testing is a multiplex qualitative and/or quantitative in vitro diagnostic device intended for the identification and determination of the antimicrobial susceptibility results of organisms detected in samples from patients with suspected microbial infections. This device is intended to aid in the determination of antimicrobial susceptibility or resistance when used in conjunction with other laboratory findings.(b)
Classification. Class II (special controls). The special controls for this device are:(1) Design verification and validation must include:
(i) Detailed device description documentation, including the device components, ancillary reagents required but not provided, a detailed explanation of the methodology, including primer/probe sequence, design, rationale for sequence selection, and details of the antimicrobial agents, as applicable.
(ii) Detailed documentation from the following analytical and clinical performance studies: limit of detection, inclusivity, precision, reproducibility, interference, cross-reactivity, carryover, and cross-contamination, quality control and additional studies, as applicable to specimen type and assay intended use.
(iii) Detailed documentation from an appropriate clinical study. The study, performed on a study population consistent with the intended use population, must compare the device performance to results obtained from well-accepted reference methods.
(iv) Detailed documentation for device software, including software applications and hardware-based devices that incorporate software.
(2) The labeling required under § 809.10(b) of this chapter must include:
(i) Limitations and protocols regarding the need for correlation of results by standard laboratory procedures, as applicable.
(ii) A detailed explanation of the interpretation of results and acceptance criteria.
(iii) A detailed explanation of the principles of operation and procedures for assay performance and troubleshooting.

Summary

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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). On the left side of the image is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the FDA logo is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.

October 23, 2024

Affinity Biosensors, LLC Nicole Holliday Director of Clinical Studies 222 East Canon Perdido Street Santa Barbara, California 93101

Re: K241324

Trade/Device Name: LifeScale Gram Negative Kit (LSGN) with the LifeScale AST system Regulation Number: 21 CFR 866.1650 Regulation Name: A Cellular Analysis System For Multiplexed Antimicrobial Susceptibility Testing Regulatory Class: Class II Product Code: SAN, LON Dated: September 23, 2024 Received: September 23, 2024

Dear Nicole Holliday:

We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

FDA's substantial equivalence determination also included the review and clearance of your Predetermined Change Control Plan (PCCP). Under section 515C(b)(1) of the Act, a new premarket notification is not required for a change to a device cleared under section 510(k) of the Act, if such change is consistent with an established PCCP granted pursuant to section 515C(b)(2) of the Act. Under 21 CFR 807.81(a)(3), a new premarket notification is required if there is a major change or modification in the intended use of a device,

1

or if there is a change or modification in a device that could significantly affect the safety or effectiveness of the device, e.g., a significant change or modification in design, material, chemical composition, energy source, or manufacturing process. Accordingly, if deviations from the established PCCP result in a major change or modification in the intended use of the device, or result in a change or modification in the device that could significantly affect the safety or effectiveness of the a new premarket notification would be required consistent with section 515C(b)(1) of the Act and 21 CFR 807.81(a)(3). Failure to submit such a premarket submission would constitute adulteration and misbranding under sections 501(f)(1)(B) and 502(o) of the Act, respectively.

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100. Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safetyreporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-device-advicecomprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part

2

3

803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Ribhi Shawar -S

Ribhi Shawar, Ph.D. (ABMM) Branch Chief, General Bacteriology and Antimicrobial Susceptibility Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K241324

Device Name

LifeScale Gram Negative Kit (LSGN) with the LifeScale AST system

Indications for Use (Describe)

The LifeScale AST system is a multiplexed in vitro diagnostic test that uses a microfluidic sensor and resonant frequency to calculate organism concentration and/or mass distribution for quantitative antimicrobial susceptibility testing (AST). Testing is performed directly on blood cultures signaled as postituous monitoring blood culture system and confirmed by Gram stain. The LifeScale AST system does not provide organism identification and is not use with polymicrobial samples. Interpretive results (Susceptible/Intermediate/Susceptible-dose dependent/Resistant) are provided for specific drug/organism combinations. Results are intended to be used in conjunction with other clinical and laboratory findings. Standard laboratory protocols for processing positive blood cultures should be followed to ensure availability of isolates for supplemental testing as needed. Additionally, subculture is necessary for the susceptibility testing of organisms present in polymicrobial samples, for testing antimicrobial agents and species not indicated for testing with the device and for epidemiologic testing and for recovery of organisms present in microbial samples.

The LifeScale AST System and the LifeScale Gram-negative Panel (LSGN) are indicated for testing of positive blood culture samples confirmed by Gram stain as containing Gram-negative organisms for the following antimicrobial agents and specific target organisms identified below:

• Amikacin: Acinetobacter spp., Escherichia coli, Klebsiella aerogenes, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruginosa

· Ampicillin: Escherichia coli

· Aztreonam: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca
· Cefazolin: Escherichia coli, Klebsiella pneumoniae, Klebsiella variicola
· Cefepime: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa

· Ceftazidime: Acinetobacter spp. (other than Acinetobacter ursingii), Escherichia aerogenes, Klebsiella oxytoca, Klebsiella variicola, Klebsiella pneumoniae, Pseudomonas aeruginosa

· Ceftazidime-avibactam: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca
Ertapenem: Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Klebsiella oxytoca

• Gentamicin: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruginosa

· Levofloxacin: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa

Meropenem: Acinetobacter spp., Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa
Meropenem-vaborbactam: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca
Piperacillin-tazobactam: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa
Trimethoprim-sulfamethoxazole: Escherichia coli, Klebsiella oxytoca, Klebsiella variicola

Type of Use (Select one or both, as applicable)

Prescription Use (Part 21 CFR 801 Subpart D)

Over-The-Counter Use (21 CFR 801 Subpart C)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

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5

510(k) Substantial Equivalence Determination Performance Summary In Compliance with Section 807.92(c)

1. Contact Details

Submitter:	Affinity Biosensors
	222 East Canon Perdido Street
	Suite 101
	Santa Barbara, California 93101
	+1 (805) 960-5100

| Correspondent: | Nicole Holliday
Director of Clinical Studies
Affinity Biosensors
222 East Canon Perdido Street
Suite 101
Santa Barbara, California 93101
+1 (440) 829-6415 |

----------------	------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

2. Device

Name of Device: LifeScale™ Gram Negative Kit (LSGN) with the LifeScale AST system Common or Usual Name: LifeScale AST system

Regulation Name:

A cellular analysis system for multiplexed antimicrobial susceptibility testing

Regulation Number:

21 CFR 866.1650 Regulatory Class: Class II Product Code: SAN, LON Predicate Device: K211815 LifeScale™ Gram Negative Kit (LSGN) with the LifeScale AST system

Purpose for Submission:

To obtain a substantial equivalence determination for the following antimicrobial i. agents to the LifeScale Gram Negative Kit (LSGN) Kit: Amikacin, Cefepime, Ceftazidime-avibactam, Gentamicin, Levofloxacin, Meropenem-vaborbactam and Piperacillin-tazobactam. The LSGN Kit is used with the LifeScale AST system for testing positive blood culture samples containing gram-negative bacilli.

Cleared Antimicrobial/Organism Combinations (K211815):

1. Ampicillin: Escherichia coli
1. Aztreonam: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca
1. Cefazolin: Klebsiella pneumoniae, Klebsiella variicola

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1. Ceftazidime: Acinetobacter baumannii, Acinetobacter baumannii/nosocomialis group, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruginosa
1. Ertapenem: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca
1. Trimethoprim-Sulfamethoxazole: Escherichia coli, Klebsiella oxytoca, Klebsiella variicola

Additional Claimed Antimicrobial/Organism Combinations (Current Submission):

1. Amikacin: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruginosa
1. Cefepime: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Pseudomonas aeruginosa
1. Ceftazidime-avibactam: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca
1. Gentamicin: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruqinosa
1. Levofloxacin: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Pseudomonas aeruginosa
1. Meropenem: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa
1. Meropenem-vaborbactam: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca
1. Piperacillin-tazobactam: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruqinosa
ii. Removal of limitations included in in the cleared LifeScale LSGN Kit with the LifeScale AST system (K211815) for Aztreonam, Ceftazidime, Ertapenem, and Cefazolin.

	Antimicrobial/Organism	Limitation
1.	Ertapenem/E. coli	Due to unacceptable performance of
ertapenem/E. coli with incubation in an
off-line incubator, perform an
alternative method of testing prior to
reporting results for ertapenem/E. coli
when panels are incubated in an off-line
incubator.	Accept Removal. Additional
clinical testing and revised IFU
provided for review
2.	Aztreonam/ K.
pneumoniae	Perform an alternative method of
testing prior to reporting results for the
following antimicrobial/organism
combination(s): Aztreonam/K.
pneumoniae	Accept Removal. Additional
clinical testing and revised IFU
provided for review
3.	Ceftazidime/ K.
pneumoniae	Perform an alternative method of
testing prior to reporting results for the
following antimicrobial/organism
combination(s): Ceftazidime/K.
pneumoniae	Accept Removal. Additional
clinical testing and revised IFU
provided for review

7

| 4. | Ceftazidime/
Acinetobacter spp. | Perform an alternative method of
testing prior to reporting results for the
following antimicrobial/organism
combination(s):
Ceftazidime/Acinetobacter spp. (other
than A. baumannii and A.
baumannii/nosocomialis group) | Revise current limitation
specifically to Acinetobacter
ursingii
Revised Limitation:
Perform an alternative method
of testing prior to reporting
results for the following
antimicrobial/organism
combination(s): Ceftazidime:
Acinetobacter ursingii (revised
IFU provided for review.) |
|----|------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 5. | Cefazolin/E. coli | Perform an alternative method of
testing prior to reporting results for the
following antimicrobial/organism
combination(s): Cefazolin/E. coli | Accept Removal. Additional
clinical testing and revised IFU
provided for review |
| 6. | Ertapenem/ K.
pneumoniae | Perform an alternative method of
testing prior to reporting results for the
following antimicrobial/organism
combination(s): Ertapenem/K.
pneumoniae | Accept Removal. Additional
clinical testing and revised IFU
provided for review |

Antimicrobials:

Table 1. LifeScale LSGN Antimicrobials and Reportable Ranges
--------------------------------------------------------------	--

Antimicrobial		Range µg/mL
		Min (≤)	Max (>)
Amikacin	AMI	4	256
*Ampicillin	AMP	2	64
*Aztreonam	AZT	1	64
*Cefazolin	FAZ	0.25	16
Cefepime	FEP	0.5	64
*Ceftazidime	TAZ	1	64
Ceftazidime-avibactam	CZA	2/4	32/4
*Ertapenem	ETP	0.12	8
Gentamicin	GEN	1	32
Levofloxacin	LEVO	0.25	16
Meropenem	MERO	0.12	16
Meropenem-vaborbactam	MEV	0.5/8	16/8
Piperacillin-tazobactam	P/T	4/4	256/4
*Trimethoprim-
sulfamethoxazole	SXT	0.25	8

*Antimicrobics cleared in K211815

8

Test Type:

The LifeScale Gram Negative Kit (LSGN) with the LifeScale AST system is a quantitative antimicrobial susceptibility test system that determines the minimum inhibitory concentration of specific organisms from positive blood culture samples.

3. Device Description

The Affinity Biosensors LifeScale Gram Negative Kit (LSGN) is a semi-automated instrument system for antimicrobial susceptibility testing (AST) directly from positive blood cultures for which the Gram stain shows gram-negative bacilli. The system uses a microfluidic sensor that detects organisms in suspension and measures differences in cell mass between bacterial suspensions incubated in the presence and absence of antibiotic. Minimum inhibitory concentrations (MICs) are determined from data obtained during sample measurement including organism concentration and/or cell mass distributions of individual organisms. The system automatically interprets the measurements to determine MIC values and interpretive results (susceptible, intermediate, or resistant) based on FDA-defined or recognized breakpoints. The organism identification determined using a platform FDA-cleared for use with positive blood culture samples is entered by the user. If the organism identification has not been entered or if the sample has not been confirmed as monomicrobial, the system provides a preliminary report that indicates that organism identification or monomicrobial status is pending. The device Instructions for Use indicates that the preliminary laboratory report should not be reported to the healthcare provider. The final report is provided to the healthcare provider when the organism identification is entered into the system and the culture is confirmed to be monomicrobial samples should not be tested with the LifeScale LSGN Kit. Preliminary results are available in most cases within four hours from initiation of the assay.

4. Intended Use/Indications for Use

Intended Use:

The LifeScale AST system is a multiplexed in vitro diagnostic test that uses a microfluidic sensor and resonant frequency to calculate organism concentration and/or mass distribution for quantitative antimicrobial susceptibility testing (AST). Testing is performed directly on blood cultures signaled as positive by a continuous monitoring blood culture system and confirmed by Gram stain. The LifeScale AST system does not provide organism identification and is not indicated for use with polymicrobial samples. Interpretive results (Susceptible/Intermediate/Susceptible-dose dependent/Resistant) are provided for specific drug/organism combinations. Results are intended to be used in conjunction with other clinical and laboratory findings. Standard laboratory protocols for processing positive blood cultures should be followed to ensure availability of isolates for supplemental testing as needed. Additionally, subculture of positive blood culture is necessary for the susceptibility testing of organisms present in polymicrobial samples, for testing antimicrobial agents and species not indicated for testing with the device and for epidemiologic testing and for recovery of organisms present in microbial samples.

Indications for Use:

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The LifeScale Gram Negative Kit (LSGN) is intended for use with the LifeScale AST system for in vitro testing of positive blood culture samples confirmed by Gram stain as containing gram-negative bacilli for the antimicrobial agents and specific target organisms identified below:

1. Ampicillin: Escherichia coli
1. Aztreonam: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca
1. Cefazolin: Escherichia coli, Klebsiella pneumoniae, Klebsiella variicola
1. Ceftazidime: Acinetobacter spp. (other than Acinetobacter ursingii), Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Klebsiella pneumoniae, Pseudomonas aeruginosa
1. Ertapenem: Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Klebsiella oxytoca
Trimethoprim-Sulfamethoxazole: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, 6. Klebsiella variicola
1. Amikacin: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruqinosa
1. Cefepime: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa
1. Ceftazidime-avibactam: Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca
1. Gentamicin: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Pseudomonas aeruginosa
1. Levofloxacin: Escherichia coli, Klebsiella pneumoniae, Klebsiella derogenes, Klebsiella oxytoca, Pseudomonas aeruginosa
1. Meropenem: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa
1. Meropenem-vaborbactam: Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Klebsiella oxytoca
1. Piperacillin-tazobactam: Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa

5. Substantial Equivalence

This submission is an addition of claims to the K211815 and does not impact the safety or effectiveness of the LifeScale AST system.

| Device &
Predicate
Device(s): | New Device
Affinity Biosensors Lifescale Gram Negative
Kit (LSGN) with the LifeScale AST system | K211815
Predicate Device
Affinity Biosensors Lifescale Gram Negative
Kit (LSGN) with the LifeScale AST system | Antimicrobial Agents | |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------|----------------------|-------------------------------|
| Device Trade
Name | Lifescale Gram Negative Kit (LSGN) with the
LifeScale AST system | Lifescale Gram Negative Kit (LSGN) with the
LifeScale AST system | | Amikacin |
| General Device Similarities | | | | Cefepime |
| Intended
Use/Indications
for Use | The LifeScale AST system is a multiplexed in vitro
diagnostic test that uses a microfluidic sensor and
resonant frequency to calculate organism | Same | | Ceftazidime-avibactam |
| concentration and/or mass distribution for
quantitative antimicrobial susceptibility testing
(AST). Testing is performed directly on blood
cultures signaled as positive by a continuous
monitoring blood culture system and confirmed by
Gram stain. The LifeScale AST system does not
provide organism identification and is not indicated
for use with polymicrobial samples. Interpretive
results (Susceptible/Intermediate/Susceptible-
dose dependent/Resistant) are provided for
specific drug/organism combinations. Results are
intended to be used in conjunction with other
clinical and laboratory findings. Standard
laboratory protocols for processing positive blood
cultures should be followed to ensure availability of
isolates for supplemental testing as needed.
Additionally, subculture of positive blood culture is
necessary for the susceptibility testing of organisms
present in polymicrobial samples, for testing
antimicrobial agents and species not indicated for
testing with the device, for epidemiologic testing
and for recovery of organisms present in microbial
samples.
The LifeScale Gram Negative Kit (LSGN) is intended
for use with the LifeScale AST system for in vitro
testing of positive blood culture samples confirmed
by Gram stain as containing gram-negative bacilli. | | | | Gentamicin |
| Sample | Blood cultures are signaled as positive by a
continuous monitoring blood culture system. | Same | | Levofloxacin |
| Inoculation
Method | Automated | Same | | Meropenem |
| Read Method | Automated | Same | | Meropenem-vaborbactam |
| Results | Report results as a minimum inhibitory
concentration (MIC) and categorical
interpretation (S, I/SDD, R) | Same | | Piperacillin-tazobactam |
| Sample Prep | Centrifugation and pipetting of sample. | Same | | Ampicillin |
| Inoculation
Method | Automated | Same | | Aztreonam |
| IVD Functions | AST | Same | | Cefazolin |
| Technology | Microfluidic and resonant frequency to
calculate organism concentration and/or mass
distribution | Same | | Ceftazidime |
| Organisms
Tested | Gram-negative bacilli | Same | | Ertapenem |
| General Device Characteristic Differences | | | | Trimethoprim-sulfamethoxazole |

10

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6. Performance Characteristics

Comparison Study

A comparison study was conducted to evaluate the performance of the LifeScale Gram Negative Kit (LSGN) with the LifeScale AST system in testing prospective clinical blood cultures confirmed positive by Gram Stain for Gram-negative bacilli. This study encompassed testing both prospective blood cultures (PBCs) and blood cultures contrived using isolates chosen to generate data required to fulfill intended use claims. All LifeScale AST sample results were compared to the reference Broth Microdilution (BMD). Each sample submitted for BMD testing was assigned a unique Trial ID, and LifeScale results were kept blinded to prevent bias. Performance was evaluated by comparing quantitative (MIC) and qualitative (S/I/SDD/R) AST results generated by the LifeScale AST System with those of the reference BMD.

Prospective PBCs consistent with the inclusion criteria were enrolled and tested at 6 US Clinical sites. For testing of prospective samples, organism ID was performed using an FDA-cleared direct from positive blood culture ID system. Testing was performed on the LifeScale AST System in accordance with the indications for use. PBC bottles were sub-cultured onto Tryptic Soy Agar supplemented with 5% Sheep Blood panels (BAP) and MacConkey Agar panels (MAC) incubated for 18-24 hours and examined for purity and colony morphology. If more than one colony type was observed, each organism was isolated for purity. All organisms isolated were identified using matrix-assisted laser desorption/ionization (MALD). Polymicrobial samples were withdrawn from the study. ID results generated using a direct from Blood Culture ID system and/or MALDI were entered into the LifeScale AST System, and a final MIC/SIR result was generated using the final LifeScale AST System software. If there was a discordant organism identification between MALDI and a Direct from Blood Culture system, MALDI ID was considered the organism's final identification.

Contrived samples were prepared from frozen isolates supplied by Affinity Biosensors, or they were prepared from contemporary isolates collected by the laboratory and agreed upon by Affinity for study inclusion. Blood cultures with the required amount of blood were spiked with isolated organisms and incubated in the blood culture system. When flagged as positive blood culture was tested on the LifeScale AST system in accordance with manufacturer's instructions for use. The PBC was sub-cultured to confirm purity. If a mixed (contaminated) culture was observed, a fresh contrived sample was prepared and tested.

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All LifeScale system testing was performed within 12 hours of the blood culture bottle being flagged as positive. LifeScale panels were read upon system confirmation of growth. Positive growth was determined automatically by the LifeScale AST system as part of the reading process. If the panel was incubated offline, it would be placed on the LifeScale system to be read. To generate the final AST report, the organism ID was entered into LifeScale AST System. The LifeScale AST System software generated the final AST results (MIC and S/I/SDD/R).

Reference testing was performed on all enrolled samples in triplicate. Testing was done in accordance with the reference protocol and was performed at two trial sites shipped isolates on transport media from the PBC purity panel following verification of pure culture. Samples contrived from laboratory stock underwent organism identification using MALDI prior to the reference site for testing. Reference testing was performed in triplicate. The procedure for Broth Microdilution reference testing follows CLSI guidance (CLSI M07).

The performance of the LifeScale AST system with the LSGN Kit was compared to the FDA-recognized reference BMD method for determining quantitative (MIC) AST results direct from Gram-negative positive blood cultures. Acceptable clinical performance was assessed across the following parameters for each antimicrobial agent on the LSGN panel; Essential Agreement (EA), Category Agreement (CA), Essential Agreement of evaluable results (Evaluable EA), Very Major Discrepancy (VMJ), Major Discrepancy (MAJ), Minor Discrepancy (MIN), Growth Failure Rate. For drug/organism group combinations where the susceptible dose-dependent category is recognized in place of the intermediate category, any errors that were observed with this category were designated as minor errors. Assessment of categorical agreement (Susceptible/ Susceptible-Dose Dependent/Intermediate/Resistant, S/SDD/I/R) was conducted utilizing FDA breakpoints (Antimicrobial Susceptibility Test Interpretive Criteria/STIC) and CLSI M100 guidelines, if applicable.

Exclusion Data

Summary of LifeScale LSGN AST Tests Initiated and Failed to Report a Result

The provided table summarizes tests initiated on the LifeScale AST system and the reasons for exclusion or incomplete results during clinical, and quality control (QC) phases. Out of 6164 tests initiated:

Plate Failures (0.32%): This category includes issues such as being unable to verify positive controls, sensor clogs detected, and the system being unable to calculate MIC.

Growth Failures (0.37%): These failures occurred due to issues related to growth during testing.

LifeScale Failures (1.12%): This category involves failures directly attributable to the LifeScale system, including software and hardware failures.

Other Reasons (0.57%): This includes a variety of reasons such as operator error, incubation time exceeding 8 hours, user cancellation, and protocol errors.

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The total percentage of tests excluded or incomplete is 2.38%, with clinical tests accounting for 0.31%, analytical tests for 1.83%, and QC tests for 0.24%.

Upon initiation of any test on the LifeScale system, results were available 97.62% (6017/6164) of the time.

Reason for Exclusion/Incomplete Test	Clinical	Analytical	QC	Overall
Plate Failures*	[5/986] 0.51%	[15/3307] 0.45%	[0/1871] 0.00%	[20/6164] 0.32%
Growth Failures	[6/986] 0.61%	[17/3307] 0.51%	[0/1871] 0.00%	[23/6164] 0.37%
LifeScale Failures**	[4/986] 0.41%	[50/3307] 1.51%	[15/1871] 0.80%	[69/6164] 1.12%
Other Reasons***	[4/986] 0.41%	[31/3307] 0.94%	[0/1871] 0.00%	[35/6164] 0.57%
Total Excluded/Incomplete Tests	[19/986] 1.93%	[113/3307] 3.42%	[15/1871] 0.80%	[147/6164] 2.38%

Table 2. Summary of LifeScale LSGN AST tests initiated and failed to report a result

*Plate Failures include: unable to verify positive controls, sensor cloq detected, system unable to calculate MIC

**LifeScale Failures include: LifeScale system software and hardware failures

***Other Reasons include: operator error, incubation time greater than 8 hours, user canceled, protocol error

Clinical Performance Data

Overall AST performance for the LifeScale LSGN Kit with the LifeScale AST System was evaluated with 8 additional antimicrobials, and an overview of the overall performance is presented in Table 4, below.

| Total
Evaluated | No. EA | EA% | No.
Eval
Tot | No.
Eval
EA | Eval EA% | No. CA | CA% | No. R | No. S | #MIN
(MIN%) | #MAJ
(MAJ%) | #VMJ
(VMJ%) |
|---------------------------------------------------------------------------------------------------------------------------|--------|--------|--------------------|-------------------|----------|--------|-------|-------|-------|----------------|----------------|----------------|
| Amikacin-Acinetobacter spp. [Breakpoints (μg/mL): ≤16 (S), 32 (I), ≥64 (R)] | | | | | | | | | | | | |
| 77 | 77 | 100.0% | 11 | 11 | 100.0% | 75 | 97.4% | 17 | 58 | 2 (2.60%) | 0 (0.00%) | 0 (0.00%) |
| aAmikacin- E. coli, K. aerogenes, K. oxytoca, K. pneumoniae, K. variicola [Breakpoints (μg/mL): ≤16 (S), 32 (I), ≥64 (R)] | | | | | | | | | | | | |
| 480 | 467 | 97.3% | 54 | 41 | 75.9% | 460 | 95.8% | 62 | 400 | 17 (3.54%) | 3 (0.75%) | 0 (0.00%) |
| aAmikacin-Pseudomonas aeruginosa [Breakpoints (μg/mL): ≤16 (S), 32 (I), ≥64 (R)] | | | | | | | | | | | | |
| 59 | 58 | 98.3% | 15 | 14 | 93.3% | 56 | 94.9% | 7 | 50 | 3 (5.08%) | 0 (0.00%) | 0 (0.00%) |
| aCefepime- E. coli, K. aerogenes, K. oxytoca, K. pneumoniae [Breakpoints (μg/mL): 16 (R)] | | | | | | | | | | | | |

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480	474	98.8%	55	49	89.1%	469	97.7%	126	352	8	(1.67%)	(0.57%)	1	(0.79%)
aGentamicin- Pseudomonas aeruginosa [Breakpoints (µg/mL): ≤4 (S), 8 (I), ≥16 (R)]
59	56	94.9%	18	15	83.3%	55	93.2%	10	47	4	(6.78%)	(0.00%)	0	(0.00%)
aLevofloxacin- E. coli, K. aerogenes, K. oxytoca, K. pneumoniae [Breakpoints (µg/mL): ≤0.5 (S), 1 (I), ≥2 (R)]
437	429	98.2%	58	50	86.2%	422	96.6%	154	267	15	(3.43%)	(0.00%)	0	(0.00%)
Levofloxacin- Pseudomonas aeruginosa [Breakpoints (µg/mL): ≤1 (S), 2 (I), ≥4 (R)]
101	97	96.0%	40	36	90.0%	89	88.1%	26	69	12	(11.88%)	(0.00%)	0	(0.00%)
Meropenem- Acinetobacter spp. [Breakpoints (µg/mL): ≤2 (S), 4 (I), ≥8 (R)]
78	75	96.2%	42	39	92.9%	76	97.4%	37	41	2	(2.56%)	(0.00%)	0	(0.00%)
aMeropenem- E. coli, K. oxytoca, K. pneumoniae [Breakpoints (µg/mL): ≤1 (S), 2 (I), ≥4 (R)]
392	359	91.6%	62	29	46.8%	379	96.7%	123	264	8	(2.04%)	(0.38%)	4	(3.25%)
aMeropenem- Pseudomonas aeruginosa [Breakpoints (µg/mL): ≤2 (S), 4 (I), ≥8 (R)]
59	57	96.6%	39	37	94.9%	53	89.8%	25	32	6	(10.17%)	(0.00%)	0	(0.00%)
aMeropenem-vaborbactam- E. coli, K. aerogenes, K. oxytoca, K. pneumoniae
[Breakpoints (µg/mL): ≤4/8 (S), 8/8 (I), ≥16/8 (R)]
442	420	95.0%	39	17	43.6%	418	94.6%	77	362	22	(4.98%)	(0.55%)	0	(0.00%)
aPiperacillin-tazobactam- Acinetobacter spp. [Breakpoints (µg/mL): ≤16/4 (S), 32/4-64/4 (I), ≥128/4 (R)]
89	82	92.1%	23	16	69.6%	84	94.4%	66	22	5	(5.62%)	(0.00%)	0	(0.00%)
aPiperacillin-tazobactam- E.coli, K. pneumoniae [Breakpoints (µg/mL): ≤8/4 (S), 16/4 (I), ≥32/4 (R)]
391	355	90.8%	67	31	46.3%	360	92.1%	198	189	25	(6.38%)	(1.58%)	3	(1.52%)
Piperacillin-tazobactam- Pseudomonas aeruginosa [Breakpoints (µg/mL): ≤8/4 (S), 16/4 (SDDb), ≥32/4 (R)]
185	174	94.1%	59	48	81.4%	173	93.5%	67	112	10	(5.41%)	(0.89%)	1	(1.49%)

Table 3. LifeScale LSGN performance: Interpretation of MIC results are based on FDA Susceptibility Test Interpretative Criteria (STIC) and the 34th edition of the CLSI M100

¶n the clinical study or in the Inoculum Density analytical study, the majority of drug/organism combinations tested with the LifeScale LSGN Kit showed MIC values equal to or at least one doubling dilution higher/lower than the reference method. Use caution when reporting drug resistance for any antimicrobial. The following drug/organism combinations showed high trending:

Amikacin Acinetobacter spp., E. coli, K. aerogenes, K. pneumoniae, K. variicola, P. aeruqinosa
Cefepime E. coli, K. aerogenes, K. oxytoca, K. pneumoniae
Ceftazidime-avibactam K. aerogenes, K. oxytoca
Gentamicin E. coli, K. pneumoniae, K. oxytoca, K. aerogenes, P. aeruginosa
Levofloxacin K. pneumoniae, K. oxytoca, K. aerogenes

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Meropenem Acinetobacter calcoaceticus species, Acinetobacter lwoffii, K. oxytoca, P. aeruginosa
Meropenem-vaborbactam K. pneumoniae, K. oxytoca, K. aerogenes
· Piperacillin-tazobactam E. coli, K. pneumoniae

The following drug/organism combinations showed low trending

Ceftazidime-avibactam - E. coli
. Piperacillin-tazobactam - A. baumannii
Meropenem-vaborbactam - E. coli

bSDD- Susceptible dose-dependent.

Amikacin (AMI)

A total of 616 samples were evaluated with Amikacin including 465 clinical (75.5%) and 151 challenge (24.5%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 97.7% and a CA of 95.9% with no VMJs (0%) and 3 MAJs (0.59%).

Species-level performance

A total of 77 Acinetobacter spp. samples were evaluated with Amikacin. The combined results from clinical and challenge testing demonstrated an EA of 97.4% with no VMJs (0%) and no MAJs (0%).
. A total of 140 E. coli samples were evaluated with Amikacin. The combined results from clinical and challenge testing demonstrated an EA of 96.4% and a CA of 95.7% with no VMJs (0%) and 2 MAJs (1.79%).
. A total of 52 K. aerogenes samples were evaluated with Amikacin. The combined results from clinical and challenge testing demonstrated an EA of 100% and a CA of 98.1% with no VMJs (0%) and no MAJs (0%).
. A total of 111 K. oxytoca samples were evaluated with Amikacin. The combined results from clinical and challenge testing demonstrated an EA of 99.1% and a CA of 99.1% with no VMJs (0%) and 1 MAJs (0.95%).
A total of 142 K. pneumoniae samples were evaluated with Amikacin. The combined results from clinical and challenge testing demonstrated an EA of 95.8% and a CA of 91.5% with no VMJs (0%) and no MAJs (0%).
. A total of 35 K. variicola samples were evaluated with Amikacin. The combined results from clinical and challenge testing demonstrated an EA of 97.1% and a CA of 100% with no VMJs (0%) and no MAJs (0%).
A total of 59 P. aeruginosa samples were evaluated with Amikacin. The combined results from clinical and challenge testing demonstrated an EA of 94.9% and a CA of 94.9% with 0 VMJs (0%) and 0 MAJ (0%).

Cefepime (FEP)

A total of 546 samples were evaluated with Cefepime including 388 clinical (71.1%) and 158 challenge (28.9%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 92.7% and a CA of 93.3% with 3 VMJs (1.64%) and 5 MAJs (1.42%).

16

Species-level performance

. A total of 139 E. coli samples were evaluated with Cefepime. The combined results from clinical and challenge testing demonstrated an EA of 94.2% and a CA of 97.1% with no VMJs (0%) and 1 MAJs (1.37%).
. A total of 53 K. aerogenes samples were evaluated with Cefepime. The combined results from clinical and challenge testing demonstrated an EA of 96.2% and a CA of 96.2% with no VMJs (0%) and no MAJs (0%).
. A total of 111 K. oxytoco samples were evaluated with Cefepime. The combined results from clinical and challenge testing demonstrated an EA of 92.8% and a CA of 92.8% with no VMJs (0%) and 1 MAJs (1.08%).
. A total of 142 K. pneumoniae samples were evaluated with Cefepime. The combined results from clinical and challenge testing demonstrated an EA of 91.5% and a CA of 96.5% with no VMJs (0%) and 1 MAJs (1.39%).
. A total of 101 P. aeruginosa samples were evaluated with Cefepime. The combined results from clinical and challenge testing demonstrated an EA of 93.1% and a CA of 84.2% with 3 VMJs (10.34%) and 13 MAJ (18.06%). Due to the lack of an intermediate breakpoint the MAJ rate can be adjusted to 2.78% since 11/13 MAJ discrepancies were in essential agreement to the reference method. Due to the high MAJ rate at 4 µg/mL the following limitation is proposed:
- For Cefepime, perform an alternative method of testing prior to reporting of results for P. о aeruginosa when the MIC is 4 µg/mL due to the occurrence of very major errors (3/29 resistant isolates, 10.34%).

Ceftazidime-avibactam (AVI)

A total of 303 samples were evaluated with Ceftazidime-avibactam including 232 clinical (76.6%) and 71 challenge (23.4%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 99.0% and a CA of 99.0% with no VMJs (0. 0%) and 3 MAJs (1.17%).

Species-level performance

. A total of 53 K. aerogenes samples were evaluated with Ceftazidime-avibactam. The combined results from clinical and challenge testing demonstrated an EA of 96.2% and a CA of 94.3% with no VMJs (0%) and 3 MAJs (5.77%). Due to the lack of an intermediate breakpoint, the MAJ rate can be adjusted to 1.92% since 2/3 MAJ discrepancies were within essential agreement to the reference method.
. A total of 111 K. oxytoca samples were evaluated with Ceftazidime-avibactam. The combined results from clinical and challenge testing demonstrated an EA of 99.1% and a CA of 100% with no VMJs (0%) and 0 MAJs (0%).

A total of 139 E. coli samples were evaluated with Ceftazidime-avibactam. The combined results from clinical and challenge testing demonstrated an EA of 100% with no VMIS (0%) and no MAJs (0%).

Gentamicin (GEN)

17

A total of 539 samples were evaluated with Gentamicin including 407 clinical (75.5%) and 132 challenge (24.5%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 98.3% and a CA of 97.2% with 1 VMJs (0.74%) and 2 MAJs (0.50%).

Species-level performance

. A total of 139 E. coli samples were evaluated with Gentamicin. The combined results from clinical and challenge testing demonstrated an EA of 99.3% and a CA of 98.6% with no VMJs (0%) and no MAJs (0%).
A total of 53 K. aerogenes samples were evaluated with Gentamicin. The combined results from clinical and challenge testing demonstrated an EA of 100% and a CA of 100% with no VMJs (0%) and no MAJs (0%).
. A total of 111 K. oxytoca samples were evaluated with Gentamicin. The combined results from clinical and challenge testing demonstrated an EA of 99.1% and a CA of 98.2% with no VMJs (0%) and 1 MAJs (1.01%).
. A total of 142 K. pneumoniae samples were evaluated with Gentamicin. The combined results from clinical and challenge testing demonstrated an EA of 97.2% and a CA of 95.8% with 1 VMJs (1.96%) and 1 MAJs (1.10%).
. A total of 35 K. variicola samples were evaluated with Gentamicin. The combined results from clinical and challenge testing demonstrated an EA of 100% and a CA of 97.1% with no VMJs (0%) and no MAJs (0%).
. A total of 59 P. aeruginosa samples were evaluated with Gentamicin. The combined results from clinical and challenge testing demonstrated an EA of 94.9% and a CA of 93.2% with 0 VMJs (0%) and 0 MAJ (0%).

Levofloxacin (LEVO)

A total of 496 samples were evaluated with Levofloxacin including 370 clinical (74.6%) and 126 challenge (25.4%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 97.6% and a CA of 94.6% with 0 VMJs (0%) and 0 MAJs (0%).

Species-level performance

A total of 137 E. coli samples were evaluated with Levofloxacin. The combined results from . clinical and challenge testing demonstrated an EA of 94.1% with no VMJs (0%) and no MAJs (0%).
A total of 53 K. aerogenes samples were evaluated with Levofloxacin. The combined results from clinical and challenge testing demonstrated an EA of 92.5% and a CA of 92.5% with no VMJs (0%) and no MAJs (0%).
A total of 108 K. oxytoca samples were evaluated with Levofloxacin. The combined results from clinical and challenge testing demonstrated an EA of 96.3% and a CA of 96.3% with no VMJs (0%) and no MAJs (0%).
A total of 139 K. pneumoniae samples were evaluated with Levofloxacin. The combined results from clinical and challenge testing demonstrated an EA of 97.8% and a CA of 95.7% with no VMJs (0%) and no MAJs 0%).
A total of 101 P. aeruginosa samples were evaluated with Levofloxacin. The combined results from clinical and challenge testing demonstrated an EA of 96.0% and a CA of 88.1% with 0 VMJs

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(0%) and 0 MAJ (0%). Most of the categorical errors were minor and the EA of evaluable results was 90.0%.

Meropenem (MERO)

A total of 529 samples were evaluated with Meropenem including 393 clinical (74.3%) and 136 challenge (25.7%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 92.8 and a CA of 96.0% with 4 VMJs (2.16%) and 1 MAJs (0.30%).

Species-level performance

. A total of 78 Acinetobacter spp. samples were evaluated with Meropenem. The combined results from clinical and challenge testing demonstrated an EA of 96.2% and a CA of 97.4% with no VMJs (0%) and no MAJs (0%).
A total of 139 E. coli samples were evaluated with Meropenem. The combined results from clinical and challenge testing demonstrated an EA of 89.9% and a CA of 97.1% with 1 VMJs (2%) and no MAJs (0%).
. A total of 111 K. oxytoca samples were evaluated with Meropenem. The combined results from clinical and challenge testing demonstrated an EA of 93.7% and a CA of 97.3% with 2 VMJs (16.67%) and no MAJs (0%). Due to the high VMJ rate the following limitation is proposed:
- Perform an alternative method of testing prior to reporting results for the following o antimicrobial/organism combination: Meropenem: K. oxytoca when the LifeScale MIC is 0.5 µg/mL due to two very major discrepancies.
. A total of 142 K. pneumoniae samples were evaluated with Meropenem. The combined results from clinical and challenge testing demonstrated an EA of 95.8% with 1 VMJs (1.64%) and 1 MAJs (1.28%).
. A total of 59 P. aeruginosa samples were evaluated with Meropenem. The combined results from clinical and challenge testing demonstrated an EA of 96.6% and a CA of 89.8% with 0 VMJs (0%) and 0 MAJ (0%). The EA of evaluable results was 94.9%.

Meropenem-vaborbactam (MEV)

A total of 442 samples were evaluated with Meropenem-vaborbactam including 331 clinical (74.9%) and 111 challenge (25.1%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 95.0% and a CA of 94.6% with no VMJs (0%) and 2 MAJs (0.55%).

Species-level performance

A total of 139 E. coli samples were evaluated with Meropenem-vaborbactam. The combined . results from clinical and challenge testing demonstrated an EA of 92.8% and a CA of 91.4% with no VMJs (0%) and no MAJs (0%).

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. A total of 53 K. aerogenes samples were evaluated with Meropenem-vaborbactam. The combined results from clinical and challenge testing demonstrated an EA of 98.1% with no VMJs (0%) and no MAJs (0%).
. A total of 110 K. oxytoca samples were evaluated with Meropenem-vaborbactam. The combined results from clinical and challenge testing demonstrated an EA of 95.5% and a CA of 94.5% with no VMJs (0%) and no MAJs (0%).
. A total of 140 K. pneumoniae samples were evaluated with Meropenem-vaborbactam. The combined results from clinical and challenge testing demonstrated an EA of 95.0% and a CA of 96.4% with no VMJs (0%) and 2 MAJs (1.83%).

Piperacillin-tazobactam

A total of 665 samples were evaluated with Piperacillin-tazobactam including 354 clinical (53.2%) and 311 challenge (46.8%) samples. The combined results from clinical and challenge testing from all claimed species demonstrated an EA of 91.9% and a CA of 92.8% with 4 VMJs (1.21%) and MAJs (1.24%).

Species-level performance

. A total of 89 A. baumannii, A. baumannii/nosocomialis group samples were evaluated with Piperacillin-tazobactam. The combined results from clinical and challenge testing demonstrated an EA of 92.1% and a CA of 94.4% with no VMJs (0%) and no MAJs (0%).
. A total of 210 E. coli samples were evaluated with Piperacillin-tazobactam. The combined results from clinical and challenge testing demonstrated an EA of 90.5% and a CA of 94.8% with 2 VMJs (2.0%) and one MAJs (0.92%).
. A total of 181 K. pneumoniae samples were evaluated with Piperacillin-tazobactam. The combined results from clinical and challenge testing demonstrated an EA of 91.2% and a CA of 89% with 1 VMJs (1.02%) and 2 MAJs (2.5%). The EA of evaluable results was 52.9%, which is not acceptable. To address this unacceptable CA, the following limitation is included in the device labeling:
- O Perform an alternative method of testing prior to reporting results for: Piperacillin/tazobactam: K. pneumoniae when the MIC is 16 µg/mL due to the occurrence of minor errors, that were in essential agreement, resulting in a category agreement below 90%.
. A total of 185 P. aeruginosa samples were evaluated with Piperacillin-tazobactam. The combined results from clinical and challenge testing demonstrated an EA of 94.1% and a CA of 93.5% with 1 VMJ (1.49%) and 1 MAJ (0.89%).

In the clinical study or the Inoculum Density analytical study, the majority of drug/organism combinations tested with the LifeScale LSGN with the LifeScale AST system showed MIC values equal to or at least one doubling dilution higher than the reference method. Use caution when reporting drug resistance for any antimicrobial. The following drug/organism combinations showed high trending:

20

. Amikacin-Acinetobacter spp., E. coli, K. aerogenes, K. pneumoniae, K. variicola, P. aeruginosa
Cefepime- E. coli, K. aerogenes, K. oxytoca, K. pneumoniae
Ceftazidime-avibactam- K. aerogenes, K. oxytoca
Gentamicin- E. coli, K. aerogenes, K. oxytoca, K. pneumoniae ●
Levofloxacin- K. aerogenes, K. oxytoca, K. pneumoniae
. Meropenem- K. oxytoca, P. aeruginosa
Meropenem-vaborbactam- K. aerogenes, K. oxytoca, K. pneumoniae
Piperacillin-tazobactam- K. pneumoniae

The following drug/organism combinations showed low trending:

Ceftazidime-avibactam - E. coli
Piperacillin-tazobactam - A. baumannii
Meropenem-vaborbactam E. coli ●

Quality Control

Strains recommended by the FDA and the new LifeScale QC strain (Enterobacter cloacae ABGNQC1) were tested for each antimicrobial agent evaluated using the LifeScale AST System LSGN Panel and the CLSI Reference Broth Microdilution Method. The quality control (QC) strains tested were Pseudomonas aeruqinosa ATCC 27853, Klebsiella pneumoniae ATCC 700603, and Enterobacter cloacae ABGNQC1. The QC testing results for Amikacin, Ceftazidime-avibactam, Gentamicin, Levofloxacin, Meropenem, Meropenem, and Piperacillin-tazobactam are detailed in Tables 4-11, indicating that this device can reliably yield acceptable QC results for >95% of tests. Cefepime, Levofloxacin, Meropenem, and Piperacillin-tazobactam incorporate data amalgamated from the initial study K211815 and the supplemental study, referred to as GAP 2. The clinical results for Amikacin, Ceftazidime-avibactam, Gentamicin, and Meropenem-vaborbactam with the new LifeScale LSGN Kit QC organism Enterobacter cloacae ABGNQC1, incorporate data from the GAP 2 study.

To validate the use of E. cloacae ABGNQC1 as a QC organism with the LifeScale LSGN, a total of 40 replicates were tested by at least two operators per media lot, spanning over a period of at least three days. A minimum of two media lots were tested, resulting in at least 80 data points using the LifeScale AST and the CLSI Reference Broth Microdilution Method. This validation study was done to establish expected QC MIC ranges for Amikacin, Ceftazidime-avibactam, Gentamicin, and Meropenemvaborbactam. In the clinical study, an additional 92 data points were tested by BMD for a total of 467 data points with >95% in-range, which supported the expected QC ranges of E. cloacae ABGNQC1 for Amikacin, Ceftazidime-avibactam, Gentamicin, and Meropenem-vaborbactam in the LifeScale LSGN clinical study.

Amikacin

-------------	---------------------------	----------------	------------------------	---------------------------

21

| | Sites → | Ref Lab
(ABIO) | ABIO | LACNY | MCW | TRI | |
|--|------------------------------------|-------------------|-----------------|-----------------|-----------------|-----------------|-----------------|
| | Enterobacter
cloacae
ABGNQC1 | 8 - 32 | 256 | | | | | |
| | Total | | 23/23
(100%) | 49/49
(100%) | 21/21
(100%) | 23/23
(100%) | 24/24
(100%) |

Table 4. LifeScale AST System QC MIC Distribution for Amikacin

Ceftazidime-avibactam

| QC Organism | Expected Range
(µg/mL) | Conc.
µg/mL | Reference
Frequency | New Device Test Frequency | | | |
|------------------------------------|---------------------------|----------------|------------------------|---------------------------|-----------------|-----------------|-----------------|
| | | Sites → | Ref Lab
(ABIO) | ABIO | LACNY | MCW | TRI |
| Enterobacter
cloacae
ABGNQC1 | 32 | | | | | |
| Total | | | 23/23
(100%) | 49/49
(100%) | 21/21
(100%) | 23/23
(100%) | 24/24
(100%) |

Table 5. LifeScale AST System QC MIC Distribution for Ceftazidime-avibactam

Cefepime

| QC Organism | Expected Range
(μg/mL) | Conc.
μg/mL | Reference
Frequency | | New Device Test Frequency | | | | | | |
|-----------------------------------------|---------------------------|----------------|------------------------|-------------------|---------------------------|-----|-----|-------|-----|-----|--|
| | | Sites → | Ref Lab
(TRI) | Ref Lab
(ABIO) | ABIO | IND | JHM | LACNY | MCW | TRI | |
| Pseudomonas
aeruginosa
ATCC 27853 | 0.5-4 | 64 | | | | | | | | |
| Total | | 89/89
(100%) | 22/22
(100%) | 48/48
(100%) | 24/24
(100%) | 53/53
(100%) | 63/63
(100%) | 27/27
(100%) | 26/26
(100%) |

Table 6. LifeScale AST System QC MIC Distribution for Cefepime

*Does not include full CLSI expected range. LifeScale MIC results of ≤0.5 µg/mL were considered acceptable.

Gentamicin

| QC Organism | Expected Range
(μg/mL) | Conc.
μg/mL | Reference
Frequency | New Device Test Frequency | | | |
|------------------------------------|---------------------------|----------------|------------------------|---------------------------|-----------------|-----------------|-----------------|
| | | Sites → | Ref Lab
(ABIO) | ABIO | LACNY | MCW | TRI |
| Enterobacter
cloacae
ABGNQC1 | 8-32 | 32 | | | | | |
| Total | | | 23/23
(100%) | 49/49
(100%) | 21/21
(100%) | 22/22
(100%) | 24/24
(100%) |

Table 7. LifeScale AST System QC MIC Distribution for Gentamicin

Levofloxacin

| QC Organism | Expected Range
(μg/mL) | Conc.
ug/mL | Reference
Frequency | | New Device Test Frequency | | | | | |
|-----------------------------------------|---------------------------|----------------|------------------------|-------------------|---------------------------|-----|-----|-------|-----|-----|
| | | Sites → | Ref Lab
(TRI) | Ref Lab
(ABIO) | ABIO | IND | JHM | LACNY | MCW | TRI |
| Pseudomonas
aeruginosa
ATCC 27853 | 0.5-4 | 16 | | | | | | | | |
| Total | | | 85/89
(95.5%) | 22/22
(100%) | 49/49
(100%) | 24/24
(100%) | 53/53
(100%) | 63/63
(100%) | 26/27
(96.3%) | 26/26
(100%) |

Table 8. LifeScale AST System QC MIC Distribution for Levofloxacin

Meropenem

| QC Organism | Expected Range
(µg/mL) | Conc.
µg/mL | Reference
Frequency | | New Device Test Frequency | | | | | |
|------------------------------------------|---------------------------|----------------|------------------------|-------------------|---------------------------|-----------------|-----------------|------------------|------------------|-----------------|
| | | Sites → | Ref
Lab
(TRI) | Ref Lab
(ABIO) | ABIO | IND | JHM | LACNY | MCW | TRI |
| *Pseudomonas
aeruginosa
ATCC 27853 | | 16 | | | | | | | | |
| Total | | | 86/86
(100%) | 22/22
(100%) | 49/49
(100%) | 24/24
(100%) | 53/53
(100%) | 60/63
(95.2%) | 26/27
(96.3%) | 26/26
(100%) |

Table 9. LifeScale AST System QC MIC Distribution for Meropenem

*Does not include full CLSI expected range. LifeScale MIC results of S0.12 µg/mL were considered acceptable.

Meropenem-vaborbactam

-------------	---------------------------	----------------	------------------------	---------------------------

24

| | | Sites → | Ref Lab
(ABIO) | ABIO | LACNY | MCW | TRI |
|------------------------------------|------|---------|-------------------|-----------------|-----------------|------------------|-----------------|
| | | 16 | | | | | |
| Total | | | 23/23
(100%) | 49/49
(100%) | 21/21
(100%) | 21/23
(91.3%) | 24/24
(100%) |

Table 10. LifeScale AST System QC MIC Distribution for Meropenem-vaborbactam

Piperacillin-tazobactam

| QC Organism | Expected Range
(µg/mL) | Conc.
µg/mL | Reference
Frequency | | New Device Test Frequency | | | | | |
|-----------------------------------------|---------------------------|----------------|------------------------|----------------------|---------------------------|-----------------|-----------------|-----------------|-----------------|-----------------|
| | | Sites → | Ref Lab
(TRI) | Ref
Lab
(ABIO) | ABIO | IND | JHM | LACNY | MCW | TRI |
| | 8 - 32 | 256 | | | | | | | | |
| Total | | | 83/83
(100%) | 52/52
(100%) | 182/182
(100%) | 25/25
(100%) | 49/49
(100%) | 69/69
(100%) | 46/46
(100%) | 47/47
(100%) |

Table 11. LifeScale AST System QC MIC Distribution for Piperacillin-tazobactam

Removal of limitations included in K211815

Additional clinical evaluation testing was performed to support the removal of limitations included in in the cleared LifeScale LSGN Kit with the LifeScale AST system (K211815) for Aztreonam, Ceftazidime, Ertapenem, and Cefazolin.

--------------------	--------	-----	-------------	-------------------	----------	--------	-----	-------	-------	----------------	----------------	----------------

25

Ertapenem - E. coli [Breakpoints (µg/mL): 0.5 (S), 2.0 (R)]
Off-line
Combined	94	85	90.4%	12	3	25%	85	90.4%	20	74	8 (8.51%) 1 (1.35%) 0 (0.00%)
On-line
Combined	108	105	97.2%	5	2	40%	104	96.3%	60	48	3 (2.78%) 1 (2.08%) 0 (0.00%)
a Aztreonam - K. pneumoniae [Breakpoints (µg/mL): 4.0 (S), 16.0 (R)]
Combined	160	144	90	21	5	23.8	151	94.4	76	83	6 (3.75%) 2 (2.41%) 1 (1.32%)
a, b Ceftazidime - K. pneumoniae [Breakpoints (µg/mL): 4.0 (S), 16.0 (R)]
Combined	160	154	96.3	22	16	72.7	155	96.9	79	79	2 (1.25%) 2 (2.53%) 1 (1.27%)
Ceftazidime - A. baumannii, A. baumannii/A. nosocomialis group, A. calcoaceticus, A. lwoffii, A. pitti, A. radioresistens, and Acinetobacter spp.
[Breakpoints (µg/mL): 8 (S), 32 (R)]
Combined	118	112	94.9	58	52	89.7	116	98.3	63	52	2 (1.69%) 0 (0.00%) 0 (0.00%)
b Cefazolin - E. coli [Breakpoints (µg/mL): 2.0 (S), 8.0 (R)]
Combined	203	197	97.0	102	96	94.1	178	87.7	117	73	22 (10.83%) 1 (1.37%) 2 (1.71%)
a, b Ertapenem - K. pneumoniae [Breakpoints (µg/mL): 0.5 (S), 2.0 (R)]
Combined	158	154	97.5	13	9	69.2	154	97.5	71	85	3 (1.90%) 0 (0.00%) 1 (1.41%)

Table 12. LifeScale LSGN performance for the removal of limitations included in K211815: Interpretation of MIC results are based on FDA Susceptibility Test Interpretative Criteria (STIC) and the 34th edition of the CLSI M100

ª K. pneumoniae tested with aztreonam, ceftazidime and ertapenem and incubated on-line and K. pneumoniae tested with ertapenem and incubated off-line showed MIC values equal to or at least one doubling dilution higher than the reference method.

b The very major error rate was increased for the following:

Ceftazidime/K. pneumoniae incubated on-line (2.6%) ●
Cefazolin/E. coli incubated off-line (2.3%) ●
Ertapenem/K. pneumoniae incubated off-line (2.9%)

° K. pneumoniae tested with ertapenem showed MIC values equal to or at least one doubling dilution higher than the reference method.

Ertapenem/E. coli - Removal of Off-line Limitation

In K211815, evaluation of the performance of on-line and off-line incubation of panels testing Ertapenem/E. coli showed unacceptable performance for this drug/organism combination when incubated offline. The following limitation was included in the device labeling:

Due to unacceptable performance of Ertapenem/E. coli with incubation in an off-line incubator, perform an alternative method of testing prior to reporting results for Ertapenem/E. coli when panels are incubated in an off-line incubator.

26

The current submission provided additional data for both incubation options. The performance for the initial (K211815) and additional data combined for both on-line and off-line incubation is acceptable, and the above limitation was removed from the device labeling.

Aztreonam/K. pneumoniae

In K211815, the data for testing Aztreonam/K. pneumoniae which showed unacceptable performance (low EA and increased major errors). The following limitation was included in the device labeling:

Perform an alternative method of testing prior to reporting results for the following antimicrobial/organism combination(s): Aztreonam/K. pneumoniae

The current submission included data from testing 54 additional K. pneumoniae isolates (seeded clinical and seeded challenge). The performance for the initial (K211815) and additional data combined for Aztreonam/K. pneumoniae is acceptable, and the above limitation was removed from the device labeling.

Ceftazidime/K. pneumoniae

In K211815, the data for testing Ceftazidime/K. pneumoniae which showed unacceptable performance (increased major errors). The following limitation was included in the device labeling:

Perform an alternative method of testing prior to reporting results for the following antimicrobial/organism combination(s): Ceftazidime/K. pneumoniae

The current submission included data from testing 54 additional K. pneumoniae isolates (seeded clinical and seeded challenge). The performance for the initial (K211815) and additional data combined for Ceftazidime/K. pneumoniae is acceptable, and the above limitation was removed from the device labeling.

Ceftazidime/Acinetobacter spp.

In K211815, the data for testing Ceftazidime with a variety of Acinetobacter spp. Performance for A. baumannii and A. baumannii/A. nosocomialis group was acceptable but combined testing of other Acinetobacter spp. showed unacceptable performance (increased very major errors). The following limitation was included in the device labeling:

Perform an alternative method of testing prior to reporting results for the following antimicrobial/organism combination(s): Ceftazidime/Acinetobacter spp. (other than A. baumannii and A. baumannii/nosocomialis group).

The current submission indicates that the unacceptable percentage of very major errors was due to very major errors observed only with Acinetobacter ursignii. The limitation could be revised to limit reporting to Acinetobacter spp. other than A. ursignii. The performance data for all Acinetobacter spp. including A. baumannii, A. baumannii/A. nosocomialis group, A. calcoaceticus, A. lwoffii, A. radioresistens,

27

and Acinetobacter spp. showed acceptable performance. The following revised limitation was included in the device labeling:

Perform an alternative method of testing prior to reporting results for the following antimicrobial/organism combination(s): Ceftazidime/Acinetobacter ursingii

Cefazolin/E. coli

In K211815, the data for testing Cefazolin/E. coli which showed unacceptable performance. The following limitation was included in the device labeling:

Perform an alternative method of testing prior to reporting results for the following antimicrobial/organism combination(s): Cefazolin/E. coli

The current submission included data from testing 66 additional E. coli isolates (seeded clinical and seeded challenge). The performance for the initial (K211815) and additional data combined for Cefazolin/E. coli is acceptable, and the above limitation was removed from the device labeling.

Ertapenem/K. pneumoniae

In K211815, the data for testing for testing Ertapenem/E. coli which showed unacceptable performance (due to increased very major errors). The following limitation was included in the device labeling:

Perform an alternative method of testing prior to reporting results for the following antimicrobial/organism combination(s): Ertapenem/K. pneumoniae

The current submission included data from testing 54 additional K. pneumoniae isolates (seeded clinical and seeded challenge). The performance for the initial (K211815) and additional data combined for Ertapenem/E. coli is acceptable, and the above limitation was removed from the device labeling.

Analytical Performance Data

Reproducibility

Initial Study Overview

Reproducibility was performed with well-characterized on-scale strain was spiked from pure culture to a BACTEC Standard Aerobic bottle. Once the blood culture bottles flagged positive, 12 aliquots were generated from each positive blood culture bottle. Aliquots were label-coded and shipped to three testing sites. Test organisms were blind-coded, and the identification of the organism was unknown to the three test sites. Each day for three days, three replicates of each test organism from a single positive blood culture were aliquoted within a few hours of the BACTEC instrument positive indication and tested at the three sites within 12 hours of the positive flag.

Upon sample receipt of the positive blood samples at each test site, the samples were processed for testing according to the LifeScale LSGN protocol. Purity verification for each LifeScale LSGN plate was

28

performed, and plates were incubated on or off-line as dictated by the LifeScale AST system workflow. LifeScale LSGN plates were read at three hours, or when the LifeScale AST system determined the growth threshold in the positive control well was acceptable.

Supplemental Study Overview

The purpose of the supplemental study was to verify that the LifeScale LSGN Kit with the LifeScale AST System provides acceptable reproducibility of on-scale MIC results for certain antimicrobials. There was an insufficient number of isolates tested for certain antibiotics. This report includes the additional testing performed for Cefepime, Ceftazidime-avibactam, and Meropenem.

All additional testing was performed at Affinity at three distinct sites within the facility. Each strain was tested in triplicate at the three internal sites, on three consecutive days. For each antibiotic, reproducibility was evaluated specific to the essential agreement between MIC results and the mode of MIC value for each strain. Data from the supplemental testing was combined with the data from the initial study.

Results and Discussion

Best-case (295%) and worst-case (>89%) reproducibility was acceptable for all antibiotics tested (Amikacin, Cefepime, Ceftazidime-avibactam, Gentamicin, Levofloxacin, Meropenem-vaborbactam, and Piperacillin-tazobactam). Inter-site reproducibility data was found to be acceptable for all antimicrobial agents. Combined Site reproducibility results for the initial and supplemental studies are summarized in Table 13.

| Antimicrobial | Best Case
No. Within 1 +/- Dil/
Total Tests (%) | Worst Case
No. Within 1 +/- Dil/
Total Tests (%) |
|-------------------------|-------------------------------------------------------|--------------------------------------------------------|
| Amikacin | Best case: 468/481 = 97.3% | Worst case: 450/481 = 93.6% |
| Cefepime | Best case: 504/509 = 99% | Worst case: 459/509 = 90.2% |
| Ceftazidime-avibactam | Best case: 345/350 = 98.6% | Worst case: 339/350= 96.9% |
| Gentamicin | Best case: 503/509 = 98.8% | Worst case: 466/509 = 91.6% |
| Levofloxacin | Best case: 373/373 = 100% | Worst case: 361/373 = 96.8% |
| Meropenem | Best case: 508/534 = 95.1% | Worst case: 477/534 = 89.3% |
| Meropenem-vaborbactam | Best case: 274/287 = 95.5% | Worst case: 261/287 = 90.9% |
| Piperacillin-tazobactam | Best case: 555/566 = 98.1% | Worst case: 521/566 = 92.0% |

Table 13. Reproducibility Data for the LifeScale LSGN Panel *

Sample Stability

29

Organisms tested:

. Escherichia coli (6 Strains)
. Klebsiella pneumoniae (3 Strains)
. Pseudomonas aeruginosa (2 Strains)
. Acinetobacter baumannii (2 Strains)

Blood Bottles Tested:

. BD BACTEC™: Standard Aerobic

Study Outline

To demonstrate sample stability at 12 hours, post positive blood cultures were tested with the LifeScale LSGN panel at the following time intervals:

. Within one hour of the bottle being flagged as positive, To.
13 +/- 0.5 hour after bottle flagged as positive, T13, when stored at 35 °C

The purpose of this study was to demonstrate that positive blood cultures tested at 12 hours post positivity (T12) and held at incubation temperature (35 °C) are equivalent to results obtained at the time of positivity (To). Contrived positive blood culture specimens (prepared in BD Standard Aerobic blood culture bottles) containing the recommended blood volume were tested within one hour of bottle ring (To) and at T13 ± 0.5 hours post bottle ring (T13). Testing at 13 hours was performed to support the stability at 12 hours post bottle ring as listed in the device labeling. Testing was performed in triplicate for each sample at each time point. Resulting MICs were compared to the modal LifeScale MIC determined at Ty. The stability acceptance criterion was ≥ 95% agreement for EA. QC was performed on each day of testing.

| Antibiotic | No. Samples
Tested | Data Points | | LifeScale T13 to LifeScale
Mode T0 |
|-----------------------------|-----------------------|-------------|-----|---------------------------------------|
| | | T0 | T13 | No. EA/Total Tested (EA%) |
| Amikacin | 13 | 39 | 39 | 36/39* (92.31%) |
| Cefepime | 11 | 33 | 33 | 31/32 (96.88%) |
| Ceftazidime-
avibactam | 11 | 33 | 33 | 33/33 (100.00%) |
| Gentamicin | 11 | 33 | 33 | 33/33 (100.00%) |
| Levofloxacin | 11 | 33 | 33 | 33/33 (100.00%) |
| Meropenem | 13 | 39 | 39 | 36/39* (92.31%) |
| Meropenem-
vaborbactam | 9 | 27 | 27 | 24/27* (88.89%) |
| Piperacillin-
tazobactam | 13 | 39 | 39 | 38/39 (97.44%) |

Table 14. Summary of Sample Stability AST Results at T13 as Compared to LifeScale LSGN Mode at To

30

TOTAL	92	276	276	264/275 (96.00%)
* Comparison to the BMD reference mode MIC resulted in an EA of 100%.

Results and Discussion

Results for Cefepime, Ceftazidime-avibactam, Gentamicin, and Piperacillin-tazobactam at T 3 meet acceptance criteria essential agreement to the MIC results obtained at To supporting the 12-hour stability claim. The essential agreement for Amikacin, Meropenem. Meropenem/vaborbactam were not acceptable (EA Escherichia coli | 10e6
CFU/mL* | 17 | 6 | 3 | 94.1% | 66.7% | 94.1% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |

33

| Ceftazidime-
avibactam | Escherichia coli | 10e9
CFU/mL | 18 | 6 | 3 | 100.0% | 100.0% | 100.0% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |
|---------------------------|---------------------------|----------------|----|---|---|--------|--------|--------|--------------|--------------|--------------|
| Ceftazidime-
avibactam | Klebsiella
pneumoniae | 10e6
CFU/mL | 4 | 2 | 0 | 100.0% | N/A | 100.0% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |
| Ceftazidime-
avibactam | Klebsiella
pneumoniae | 10e9
CFU/mL | 7 | 3 | 0 | 100.0% | N/A | 100.0% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |
| Ceftazidime-
avibactam | Pseudomonas
aeruginosa | 10e6
CFU/mL | 5 | 2 | 5 | 60.0% | 60.0% | 100.0% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |
| Ceftazidime-
avibactam | Pseudomonas
aeruginosa | 10e9
CFU/mL | 6 | 2 | 6 | 100.0% | 100.0% | 100.0% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |

Table 17. Inoculum Density Performance Data, Ceftazidime-avibactam.

*The LifeScale MIC values tended to be equal to or at least one doubling dilution lower than the reference broth microdilution method.

GENTAMICIN (GEN)		Performance Data
Antibiotic	Genus/Species	Incubation
Category	#Samples	#Organisms	#Evaluable	EA%	EA%
Evaluable	CA%	#VMJ
(VMJ%)	#MAJ
(MAJ%)	#MIN
(MIN%)
Gentamicin	Escherichia
coli	10e6
CFU/mL	17	6	9	100.0%	100.0%	94.1%	0
(0.00%)	0
(0.00%)	1
(5.88%)
Gentamicin	Escherichia
coli	10e9
CFU/mL*	18	6	9	100.0%	100.0%	72.2%	0
(0.00%)	0
(0.00%)	5
(27.78%)
Gentamicin	Klebsiella
pneumoniae	10e6
CFU/mL	4	2	3	75.0%	66.7%	75.0%	0
(0.00%)	0
(0.00%)	1
(25.00%)
Gentamicin	Klebsiella
pneumoniae	10e9
CFU/mL	7	3	1	100.0%	100.0%	85.7%	0
(0.00%)	0
(0.00%)	1
(14.29%)
Gentamicin	Pseudomonas
aeruginosa	10e6
CFU/mL	5	2	5	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Gentamicin	Pseudomonas
aeruginosa	10e9
CFU/mL	6	2	6	100.0%	100.0%	66.7%	0
(0.00%)	0
(0.00%)	2
(33.33%)

Table 18. Inoculum Density Performance Data, Gentamicin.

The LifeScale MIC values tended to or at least one doubling dilution higher than the reference broth microdilution method

LEVOFLOXACIN (LEVO)		Performance Data
Antibiotic	Genus/Species	Incubation
Category	#Samples	#Organisms	#Evaluable	EA%	EA%
Evaluable	CA%	#VMJ
(VMJ%)	#MAJ
(MAJ%)	#MIN
(MIN%)
Levofloxacin	Escherichia
coli	10e6
CFU/mL	17	6	6	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Levofloxacin	Escherichia
coli	10e9
CFU/mL	18	6	6	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Levofloxacin	Klebsiella
pneumoniae	10e6
CFU/mL	4	2	1	100.0%	100.0%	75.0%	0
(0.00%)	0
(0.00%)	1
(25.00%)
Levofloxacin	Klebsiella
pneumoniae	10e9
CFU/mL	7	3	6	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Levofloxacin	Pseudomonas
aeruginosa	10e6
CFU/mL	5	2	5	100.0%	100.0%	40.0%	0
(0.00%)	0
(0.00%)	3
(60.00%)
Levofloxacin	Pseudomonas
aeruginosa	10e9
CFU/mL	6	2	6	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)

Table 19. Inoculum Density Performance Data, Levofloxacin

34

MEROPENEM (MERO)		Performance Data
Antibiotic	Genus/Species	Incubation
Category	#Samples	#Organisms	#Evaluable	EA%	EA%
Evaluable	CA%	#VMJ
(VMJ%)	#MAJ
(MAJ%)	#MIN
(MIN%)
Meropenem	Escherichia
coli	10e6
CFU/mL	217	6	0	100.0%	N/A	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem	Escherichia
coli	10e9
CFU/mL	18	6	0	100.0%	N/A	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem	Acinetobacter
baumannii	10e6
CFU/mL	5	2	3	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem	Acinetobacter
baumannii	10e9
CFU/mL	6	2	3	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem	Klebsiella
pneumoniae	10e6
CFU/mL	4	2	4	75.0%	75.0%	25.0%	0
(0.00%)	0
(0.00%)	3
(75.00%)
Meropenem	Klebsiella
pneumoniae	10e9
CFU/mL	7	3	4	85.7%	75.0%	71.4%	0
(0.00%)	0
(0.00%)	2
(28.57%)
Meropenem	Pseudomonas
aeruginosa	10e6
CFU/mL	5	2	5	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem	Pseudomonas
aeruginosa	10e9
CFU/mL	6	2	6	100.0%	100.0%	50.0%	0
(0.00%)	0
(0.00%)	3
(50.00%)

Table 20. Inoculum Density Performance Data, Meropenem.

| MEROPENEM-VABORBACTAM

(MEV)		Performance Data
Antibiotic	Genus/Species	Incubation
Category	#Samples	#Organisms	#Evaluable	EA%	EA%
Evaluable	CA%	#VMJ
(VMJ%)	#MAJ
(MAJ%)	#MIN
(MIN%)
Meropenem-
vaborbactam	Escherichia coli	10e6
CFU/mL	17	6	0	100.0%	N/A	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem-
vaborbactam	Escherichia coli	10e9
CFU/mL	18	6	0	100.0%	N/A	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem-
vaborbactam	Klebsiella
pneumoniae	10e6
CFU/mL	4	2	4	50.0%	50.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)
Meropenem-
vaborbactam	Klebsiella
pneumoniae	10e9
CFU/mL	7	3	4	100.0%	100.0%	100.0%	0
(0.00%)	0
(0.00%)	0
(0.00%)

Table 21. Inoculum Density Performance Data, Meropenem-vaborbactam.

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| Antibiotic | Genus/Species | Incubation
Category | #Samples | #Organisms | #Eval
uable | EA% | EA%
Evaluable | CA% | #VMJ
(VMJ%) | #MAJ
(MAJ%) | #MIN
(MIN%) |
|-----------------------------|----------------------------|------------------------|----------|------------|----------------|--------|------------------|--------|----------------|----------------|----------------|
| Piperacillin-
tazobactam | Escherichia coli | 10e6
CFU/mL | 29 | 8 | 17 | 86.2% | 76.5% | 96.6% | 0
(0.00%) | 1
(5.88%) | 0
(0.00%) |
| Piperacillin-
tazobactam | Escherichia coli | 10e9
CFU/mL* | 18 | 6 | 7 | 94.4% | 85.7% | 88.9% | 0
(0.00%) | 0
(0.00%) | 2
(11.11%) |
| Piperacillin-
tazobactam | Acinetobacter
baumannii | 10e6
CFU/mL | 5 | 2 | 2 | 100.0% | 100.0% | 60.0% | 0
(0.00%) | 0
(0.00%) | 2
(40.00%) |
| Piperacillin-
tazobactam | Acinetobacter
baumannii | 10e9
CFU/mL | 6 | 2 | 6 | 66.7% | 66.7% | 50.0% | 0
(0.00%) | 0
(0.00%) | 3
(50.00%) |
| Piperacillin-
tazobactam | Klebsiella
pneumoniae | 10e6
CFU/mL | 16 | 4 | 13 | 93.8% | 92.3% | 62.8% | 0
(0.00%) | 0
(0.00%) | 3
(31.25%) |
| Piperacillin-
tazobactam | Klebsiella
pneumoniae | 10e9
CFU/mL | 7 | 3 | 3 | 100.0% | 100.0% | 100.0% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |
| Piperacillin-
tazobactam | Pseudomonas
aeruginosa | 10e6
CFU/mL | 25 | 5 | 25 | 92.0% | 92.0% | 92.0% | 2
(8.00%) | 0
(0.00%) | 0
(0.00%) |
| Piperacillin-
tazobactam | Pseudomonas
aeruginosa | 10e9
CFU/mL | 6 | 2 | 6 | 100.0% | 100.0% | 100.0% | 0
(0.00%) | 0
(0.00%) | 0
(0.00%) |

Table 22. Inoculum Density Performance Data, Piperacillin-tazobactam.

The LifeScale MIC values tended to or at least one doubling dilution higher than the reference broth microdilution method

Media Equivalence

LifeScale LSGN Blood Bottle Compatibility Organisms tested:

Escherichia coli (5 Strains)
Klebsiella pneumoniae (3 Strains)
Pseudomonas aeruginosa (2 Strains)
. Acinetobacter baumannii (2 Strains)

Blood Bottles Tested:

BD BACTEC™: Standard Aerobic, Standard Anaerobic, Plus Aerobic, Lytic Anaerobic .
BacT/ALERT™: Standard Aerobic, Standard Anaerobic
VersaTREK™: REDOX 1 Aerobic media, REDOX 2 Anaerobic media

Study Outline

A minimum of 12 strains were tested using each blood culture media type. Testing was performed on replicates of ten (10) per organism/media type. Each organism tested was spiked into the blood culture media to be tested, at a target concentration of 1,000-10,000 CFU per mL. Testing was conducted with the eight media types listed above.

36

BACTEC bottles were placed in the automated blood culture instrument. The remaining blood bottle types were incubated off-line at 35 °C +/- 2 °C. The VersaTREK Redox2 bottle was not mixed in accordance with the VersaTREK IFU. A VersaTREK connector was attached to the VersaTREK Redox1 bottle, which is required for incubation on the VersaTREK system to detect pressure changes and prevent gas build up. It was used in this study to prevent dangerous gas build up within the mixing VersaTREK REDOX bottles. The connectors were inserted in the bottle top prior to incubation and removed after incubation.

The BACTEC incubation time was used as a guide to incubation time for the equivalent BacT/ALERT and VersaTREK bottles. Prior to LifeScale AST testing, cell counts were performed on LifeScale AST to determine whether these bottles had reached bottle ring concentration (10° CFU/ml). BacT/ALERT and VersaTREK bottles for which LifeScale AST cell counts indicate concentrations less than bottle ring concentrations, (10°CFU/ml), were returned to the off-line incubator within 20 minutes.

All susceptibility testing was performed using the LifeScale LSGN Kit with the LifeScale AST System direct from spiked positive blood cultures, per the LifeScale LSGN Instructions for Use.

A single LifeScale LSGN panel was prepared from each positive blood culture bottle. LifeScale LSGN plates that were incubated on the LifeScale AST system were read automatically approximately 3 hours from incubation or when sufficient growth had taken place. Plates incubated off-line were read when the LifeScale AST system called for them in accordance with the LifeScale LSGN Instructions for Use.

Since all other analytical studies used a single bottle type (i.e., BD BACTEC Standard Aerobic Media), and all bottle types were tested in the clinical study, results from each media/antimicrobial were directly compared to LifeScale AST modal MICs from the BD BACTEC Standard Aerobic Media (i.e., the "comparator").

Essential Agreement (EA) was calculated and compared to the LifeScale AST mode MIC results from the BD BACTEC Standard Aerobic Media, for each antimicrobial and blood culture media.

An EA agreement of ≥95% for the various blood culture media compared to LifeScale AST mode MICs from the BD BACTEC Standard Aerobic Media for each antimicrobial confirms that the different blood culture media do not affect the MIC results.

Results and Discussion

The performance of various blood bottle types was evaluated for Amikacin, Cefepime, Ceftazidimeavibactam, Gentamicin, Levofloxacin, Meropenem-vaborbactam and Piperacillintazobactam.

A total of 888 samples were tested on the LifeScale AST system. There were 10 "Failed" samples whose measurement failed to complete. There were 4 "Unreported" occurrences when the measurement of a plate was completed but the system could not give an MIC for a specific antibiotic due to a failed measurement of individual wells, an empty well, or an anomalous growth pattern. There were a total of 90 withdrawn samples due to Acinetobacter and Pseudomonas data collected with Anaerobic blood bottles.

37

All blood culture media demonstrated ≥95% EA for each antimicrobial when compared to the LifeScale AST modal MICs from the BD BACTEC Standard Aerobic Media, except Amikacin, Gentamicin and Meropenem.

Amikacin

All blood bottle types showed excellent performance with EA ≥95%, except Standard Aerobic (BMX) and REDOX 1 aerobic media.

Acinetobacter baumannii varied across the blood bottle types. The Standard Aerobic (BD) and Plus Aerobic (BD) bottles demonstrated 100% EA, indicating reliable detection. However, the Standard Aerobic (BMX) bottle type showed a decrease in performance with an EA of 84.2%, and the REDOX 1 aerobic bottle at 77.8% EA, suggesting potential limitations in these bottle types for detecting A. baumannii.

Gentamicin

All blood bottle types showed excellent performance with EA ≥95%, except Plus Aerobic (BD), Standard Aerobic (BMX) and Standard Anaerobic (BMX).

Klebsiella pneumoniae varied across blood bottle types and conditions. The Standard Aerobic (BD) bottle type showed high EA (96.7%). REDOX 1 Aerobic media demonstrated 100% EA, indicating reliable agreement of Klebsiella pneumoniae in aerobic conditions. However, some bottle types, such as Plus Aerobic (BD), Standard Aerobic (BMX) and Standard Anaerobic (BMX), exhibited lower EA. The low EA for these combinations is due to the results of a single strain, K. pneumoniae IHMA1427927 with a bimodal distribution across multiple bottle types lower the performance:

Gentamicin/Plus Aerobic (BD): K. pneumoniae IHMA1427927 (EA: 1/10) Gentamicin/Standard Aerobic (BMX): K. pneumoniae IHMA1427927 (EA: 0/10) Gentamicin/Standard Anaerobic (BMX): K. pneumoniae IHMA1427927 (EA: 1/10)

Meropenem

All blood bottle types showed excellent performance with EA ≥95%, except REDOX 1 Aerobic Media and the Standard Anaerobic (BMX) media.

Escherichia coli performance showed variability across bottle types. The Standard Aerobic (BMX) bottle type demonstrated 100% EA, indicating robust performance, while REDOX 1 Aerobic media showed slightly lower EA. Bottle types including the REDOX 1 Aerobic Media and the Standard Anaerobic (BMX) media exhibited lower EA. The low EA for these combinations is due to the results of a single strain, E. coli JMI1054207 with various MIC results across multiple bottle types lower the performance:

Meropenem/Standard Anaerobic (BMX): E. coli JMI1054207 (EA: 0/10) Meropenem/REDOX 1 Aerobic: E. coli JMI1054207 (EA: 0/10)

Conclusion

Amikacin, cefepime, ceftazidime-avibactam, levofloxacin, gentamicin, meropenemvaborbactam, and piperacillin-tazobactam were assessed for their susceptibility testing against various

38

bacterial strains across different blood bottle types and aerobic conditions. Results for most drug/organism combinations for claimed species showed good performance with all blood culture bottles with the following exceptions:

Amikacin/A. baumannii with Standard Aerobic (BMX) and REDOX 1 aerobic bottle
Overall, the study suggests that these antibiotics can effectively assess the susceptibility of bacterial strains in blood cultures, but there may be variations in performance depending on the specific antibiotic, bacterial strain, and blood bottle type used resulting in potential limitations.

Interfering Substances Organisms tested:

1.Escherichia coli (7 Strains) 2. Pseudomonas aeruginosa (3 Strain) 3. Acinetobacter baumannii (2 Strain) 4. Klebsiella pneumoniae (3 Strains)

Blood Bottle Tested:

BD BACTEC™: Standard Aerobic

Interfering substances	Testing Concentrations
Conjugated bilirubin	0.003 mg/mL
Unconjugated bilirubin	0.003 - 0.012 mg/mL
Gamma-globulin	6 - 13 mg/mL
Hemoglobin	100 mg/mL
Triglycerides	5 mg/mL
White cells	4.5X106 - 1.0X 107 cells/mL
Heparin	330 units/dL
Platelets	≥450,000 platelets/µL

Interfering Substances

Table 23. Interferring substances and concentrations used in the study.

Study Outline

This study assesses the impact of potentially interfering substances on the LifeScale LSGN Kit with ifeScale AST system performance by adding a potentially interfering substance to blood culture media containing a test organism and blood. The test blood culture bottle is incubated in a blood culture system until the blood culture is flagged positive. The positive blood culture is then tested on the LifeScale

39

system and the results for the six antibiotics on the LifeScale LSGN panel are compared to those for positive blood cultures that do not contain interfering substances.

BACTEC Standard Aerobic media was used for testing for each interferent was carried out with a minimum of fifteen (15) test organisms. Each interfering substance was tested in triplicate for each test organism/media combination.

Only bottles that flagged positive within 48 hours of inoculation were tested in the LifeScale AST system. A bottle containing no interfering substance was tested in triplicate each time testing was performed with interfering substances. When the blood culture was flagged positive, a LifeScale LSGN AST was performed directly from the positive blood culture using the LifeScale AST system as described in the LifeScale manual.

Interfering Substances

The interfering substance and 10 mL of whole blood, the volume recommended by the manufacturer, were added to the blood culture bottle. The blood culture was inoculated with the test organism and placed onto the BACTEC Blood culture instrument until it flagged positive.

The effect of antimicrobial agents as interfering substances was not evaluated. The following limitation applies:

Potential interference by antimicrobial aqents that may be present in a patient blood specimen has not been established with the Affinity LifeScale LSGN Kit. Use caution when interpreting results if information is available about the patient treatment with antimicrobial agents.

Essential Agreement (EA) was determined by comparing MICs for bottles containing interfering substances to the mode of MICs for bottles not containing interfering substances for each organism under test. EA ≥ 95% was acceptable and indicated that the interfering substance had no substantial impact on results. Analysis was performed for each interfering substance and both media types.

Results and Discussion

Essential Agreement for Interfering Substances.

For a majority of the antimicrobials in this study, EA exceeded 95% for most substances. Discrepancies reduced EA to

Intended Use / Indications for Use

Product codes (comma separated list FDA assigned to the subject device)

Device Description

Mentions image processing

Mentions AI, DNN, or ML

Input Imaging Modality

Anatomical Site

Indicated Patient Age Range

Intended User / Care Setting

Description of the training set, sample size, data source, and annotation protocol

Description of the test set, sample size, data source, and annotation protocol

Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)

§ 866.1650 A cellular analysis system for multiplexed antimicrobial susceptibility testing.

Ribhi Shawar -S

Indications for Use

Device Name

Indications for Use (Describe)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

510(k) Substantial Equivalence Determination Performance Summary In Compliance with Section 807.92(c)

1. Contact Details

2. Device

Regulation Name:

Regulation Number:

Purpose for Submission:

Cleared Antimicrobial/Organism Combinations (K211815):

Additional Claimed Antimicrobial/Organism Combinations (Current Submission):

Antimicrobials:

Test Type:

3. Device Description

4. Intended Use/Indications for Use

Intended Use:

Indications for Use:

5. Substantial Equivalence

6. Performance Characteristics

Comparison Study

Exclusion Data

Summary of LifeScale LSGN AST Tests Initiated and Failed to Report a Result

Clinical Performance Data

Table 3. LifeScale LSGN performance: Interpretation of MIC results are based on FDA Susceptibility Test Interpretative Criteria (STIC) and the 34th edition of the CLSI M100

Amikacin (AMI)

Species-level performance

Cefepime (FEP)

Species-level performance

Ceftazidime-avibactam (AVI)

Species-level performance

Gentamicin (GEN)

Species-level performance

Levofloxacin (LEVO)

Species-level performance

Meropenem (MERO)

Species-level performance

Meropenem-vaborbactam (MEV)

Species-level performance

Piperacillin-tazobactam

Species-level performance

Trending

Quality Control

Amikacin

Ceftazidime-avibactam

Cefepime

Gentamicin

Levofloxacin

Meropenem

Meropenem-vaborbactam

Piperacillin-tazobactam

Removal of limitations included in K211815

Table 12. LifeScale LSGN performance for the removal of limitations included in K211815: Interpretation of MIC results are based on FDA Susceptibility Test Interpretative Criteria (STIC) and the 34th edition of the CLSI M100

Ertapenem/E. coli - Removal of Off-line Limitation

Aztreonam/K. pneumoniae

Ceftazidime/K. pneumoniae

Ceftazidime/Acinetobacter spp.

Cefazolin/E. coli

Ertapenem/K. pneumoniae

Analytical Performance Data

Reproducibility

Initial Study Overview

Supplemental Study Overview

Results and Discussion

Table 13. Reproducibility Data for the LifeScale LSGN Panel *