SYSTEM U3 FOR TRIMETHOPRIM/SULFAMETHOXAZOLE by AB BIODISK

System U3™ is a qualitative technique for antimicrobial susceptibility testing of nonfastidious Gram negative and Gram positive aerobic bacteria, such as Enterobacteriaceae, Pseudomonas, Staphylococcus and Enterococcus species. The system comprises an antibiotic gradient with MIC break-point concentrations and is used to determine the susceptibility categories of microorganisms to different antimicrobial agents, as tested on agar media using overnight incubation.

This 510(k) application is for System U3/Trimethoprim/sulfamethoxazole susceptibility testing based on the MIC breakpoints of Susceptible ≤ 2 µg/ml and Resistant ≥ 4 µg/ml for use with non-fastidious Gram negative and Gram positive aerobic bacteria.

Device Description

The system comprises an antibiotic gradient with MIC break-point concentrations and is used to determine the susceptibility categories of microorganisms to different antimicrobial agents, as tested on agar media using overnight incubation.

AI/ML Overview

This document is a 510(k) premarket notification decision letter from the FDA for the "System U3™ for Trimethoprim/sulfamethoxazole." It primarily focuses on the regulatory approval and substantial equivalence to a predicate device, rather than detailed performance and study information of the device itself.

Therefore, much of the requested information regarding acceptance criteria, study details, sample sizes, expert qualifications, and ground truth establishment is not available in this document. This letter confirms approval and outlines regulatory responsibilities but does not contain the technical study data.

However, I can extract the following:

1. A table of acceptance criteria and the reported device performance:

Based on the "Indications For Use" section, the acceptance criteria relates to the determination of susceptibility categories using specific MIC breakpoints for Trimethoprim/sulfamethoxazole. No specific performance metrics (like sensitivity, specificity, accuracy) or a table comparing them to acceptance criteria are provided in this regulatory letter.

Acceptance Criteria (MIC Breakpoints)	Reported Device Performance
Susceptible ≤ 2 µg/ml	Not reported in this document
Resistant ≥ 4 µg/ml	Not reported in this document

The document states: "This 510(k) application is for System U3/Trimethoprim/sulfamethoxazole susceptibility testing based on the MIC breakpoints of Susceptible ≤ 2 µg/ml and Resistant ≥ 4 µg/ml for use with non-fastidious Gram negative and Gram positive aerobic bacteria." This defines the criteria the device aims to meet.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective):

Sample size for the test set: Not available in this document.
Data provenance: Not available in this document.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

Not available in this document.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

Not available in this document.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

Not applicable/Not available. This device is an in vitro diagnostic for antimicrobial susceptibility testing, not an AI-assisted imaging device that would typically involve human readers interpreting images.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

This device, System U3™, is described as a "qualitative technique for antimicrobial susceptibility testing" and an "antibiotic gradient with MIC break-point concentrations." It functions as an in vitro diagnostic test. It's likely designed for standalone performance in a laboratory setting to determine susceptibility, meaning the result is read directly from the test. However, the exact "standalone performance" metrics (like accuracy vs. a gold standard) are not provided in this regulatory letter.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

For antimicrobial susceptibility testing, the "ground truth" (or reference method) typically involves a standardized reference method for MIC determination, such as broth microdilution or agar dilution, against which the device's results are compared. The document does not specify the exact ground truth method used in the studies supporting this 510(k) submission.

8. The sample size for the training set:

Not available in this document. This document pertains to a 510(k) submission, not typically a machine learning device that requires "training sets" in the same way. Performance data would usually come from validation studies.

9. How the ground truth for the training set was established:

Not applicable/Not available, as this is not an AI/machine learning device that would have a "training set" in the conventional sense. The ground truth for validation (if discussed) would likely be established using a reference method for antimicrobial susceptibility testing.

Summary

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Nov 25 1998

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Anne Bolmström President AB BIODISK Dalvägen 10 S-169 56 Solna Sweden

Re: K983259 Trade Name: System U3TM for Trimethoprim/sulfamethoxazole Regulatory Class: II Product Code: JWY Dated: September 14, 1998 Received: September 16, 1998

Dear Ms. Bolmström:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we 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 (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. 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.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (OS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

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Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at (770)488-7655.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll free number (800) 638-2041 or at (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html"

Sincerely yours,

Steven Sutman

Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known):

Device Name: System U3™ for Trimethoprim/sulfamethoxazole

Indications For Use:

For in vitro diagnostic use:

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

	Wooley Debaes
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	vision of Clinical Laboratory Devices
(k) Number	K983259

Prescription Use (Per 21 CFR 801.109) OR

Over-The Counter Use

(Optional Format 1-2-96)

Regulation Number and Section

§ 866.1640 Antimicrobial susceptibility test powder.

(a)
Identification. An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).