VIDAS® C. difficile Toxin A & B (CDAB) assay is an automated test for use on the VIDAS instruments for the qualitative detection of Clostridium difficile toxin A and toxin B in stool specimens using the ELFA technique (Enzyme-Linked Fluorescent Assay). The assay principle combines a two-step enzyme immunoassay sandwich method with a final fluorescent detection (ELFA). The Solid Phase Receptacle (SPR), a pipette tip-like device, serves as the solid phase as well as the pipetting device for the assay. The assay reagents are ready-to-use and pre-dispensed in the sealed reagent strips (STRs). Each of the four reaction steps are performed automatically by the VIDAS instrument. The reaction medium (sample/conjugate mixture) is cycled in and out of the SPR several times. Each step is followed by a wash cycle which eliminates unbound components. At the end of the VIDAS CDAB assay, results are automatically calculated by the VIDAS instrument. A test value as well as the qualitative result (positive, negative or equivocal) are provided on the result sheet for each sample.

AI/ML Overview

This document describes the regulatory submission for the VIDAS® CDAB Assay, a device for detecting Clostridium difficile toxins.

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" as pass/fail thresholds for numerical values. Instead, it presents performance data used to demonstrate substantial equivalence to a predicate device. The performance data is as follows:

Item	Device [VIDAS CDAB] Performance	Predicate [Premier Toxins A&B] Performance (for comparison)
Non-clinical (Analytical) Comparison
Precision/Reproducibility	Total precision: 7.4 – 37.6% CVInter-assay precision: 6.8 – 26.8% CVIntra-assay precision: 2.9 – 26.3% CV	Within run: 4.1 – 28.9% CVBetween run: 6.2 – 31.7% CV
C. difficile strain types	A+/B+: 100% (23/23)A-/B+: 83% (15/18) 3 of the A-/B+ strains gave equivocal results	A+/B+: 100% (25/25)A-/B+: 100% (3/3)
Limit of Detection (stool)	Toxin A: ≥ 7.73 ng/mLToxin B: ≥ 4.55 ng/mL	Toxin A: ≥ 1.4 ng/mLToxin B: ≥ 2.4 ng/mL
Clinical Studies Comparison
Positive Agreement (vs Predicate)	81.3% (95% CI: 73.4–87.6%)	N/A (Predicate is the comparator)
Negative Agreement (vs Predicate)	99.5% (95% CI: 98.8 – 99.9%)	N/A
Global Agreement (vs Predicate)	97.1% (95% CI: 95.9–98.1%)	N/A

The acceptance criterion, though not quantitatively defined in a table as a "pass/fail" value, is implied by the conclusion of "substantial equivalence" to the predicate device. This suggests that the reported device performance was deemed acceptably similar or competitive to the predicate's performance across these metrics.

2. Sample Size Used for the Test Set and Data Provenance:

Sample Size for Clinical Studies: 1011 specimens.
Data Provenance: The clinical studies were conducted in the US and Europe. The document does not explicitly state whether the data was retrospective or prospective. Given the typical nature of device submissions, it is likely a mix or primarily prospective collection for the clinical comparison, but this is not explicitly stated.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:

The document does not mention the use of experts to establish a "ground truth" for the test set in the context of human interpretation of results. The clinical study performance is evaluated as "agreement versus Predicate," meaning the results of the VIDAS CDAB assay are compared directly against the results obtained from the Meridian Premier Toxins A&B assay (the predicate device). Therefore, the predicate device's results implicitly serve as the comparative standard here, rather than a separate expert-adjudicated ground truth.

4. Adjudication Method for the Test Set:

Not applicable. As noted above, the VIDAS CDAB assay's performance was compared against the predicate device (Meridian Premier Toxins A&B assay), rather than an expert-adjudicated ground truth.

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:

This is not applicable. The VIDAS® CDAB Assay is an automated in-vitro diagnostic device for the qualitative detection of Clostridium difficile toxins, not an AI-powered diagnostic tool requiring human interpretation or assistance. Therefore, an MRMC study with human readers and AI assistance would not be relevant.

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

Yes, this was a standalone performance study. The VIDAS® CDAB assay is described as an "automated test" that "automatically calculated by the VIDAS instrument." Its performance metrics (precision, strain detection, limit of detection, and agreement with the predicate) are inherently standalone without human intervention in the result determination.

7. The Type of Ground Truth Used:

For the clinical studies, the "ground truth" was effectively the results obtained from the predicate device (Meridian Premier Toxins A&B). The study's aim was to demonstrate substantial equivalence by comparing the VIDAS CDAB assay's output to the predicate's output.

For the analytical studies (precision, strain types, limit of detection), the ground truth would be based on characterized samples and known concentrations/strains used in the laboratory setting.

8. The Sample Size for the Training Set:

The document does not provide information regarding a separate "training set" for the VIDAS® CDAB assay. Given that it's described as an immunoassay (ELFA technique) rather than a machine learning or AI-driven algorithm, a distinct "training set" in the context of algorithm development is not typically applicable in the same way. The assay development would involve extensive R&D and optimization, but not generally a discrete "training set" as understood in AI/ML.

9. How the Ground Truth for the Training Set was Established:

Not applicable, as a discrete training set for an algorithm is not described or implied for this immunoassay device. The "ground truth" during the development and optimization phases would be based on well-characterized laboratory samples with known C. difficile toxin presence and concentrations, similar to how analytical performance metrics are established.

Summary

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077138

DEC 2 1 2007

510(k) SUMMARY

VIDAS® CDAB Assay

A. Submitter Information

Submitter's Name:Address:	bioMérieux, Inc.595 Anglum RoadHazelwood, MO 63042
Contact Person:	Nikita S. Mapp
Phone Number:	314-731-7474
Fax Number:	314-731-8689
Date of Preparation:	July 1, 2007 (revised Dec. 20, 2007)
B. Device NameTrade Name:	VIDAS® CDAB
Common Name:	Clostridium difficile Enzyme Immunoassay
Classification Name:	21 CFR 866.2660, Product Code LLHReagents, Clostridium Difficile Toxin
C. Predicate Device NameTrade Name:	Meridian Premier Toxins A&B

D. Device Description

The assay principle combines a two-step enzyme immunoassay sandwich method with a final fluorescent detection (ELFA). The Solid Phase Receptacle (SPR), a pipette tip-like device, serves as the solid phase as well as the pipetting device for the assay. The assay reagents are ready-to-use and pre-dispensed in the sealed reagent strips (STRs). The individual kit components are described in detail on the following pages.

Each of the four reaction steps are performed automatically by the VIDAS instrument. The reaction medium (sample/conjugate mixture) is cycled in and out of the SPR several times. Each step is followed by a wash cycle which eliminates unbound components.

Step 1: Toxin A and/or toxin B present in the sample binds with the anti-toxin A antibodies (rabbit polyclonal) and anti-toxin B antibodies (mouse monoclonal) coated on the interior wall of the SPR.

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Binding between toxin A and anti-toxin A antibodies (mouse monoclonal) conjugated Step 2: with biotin. Binding between toxin B and anti-toxin B antibodies (mouse monoclonal) conjugated with biotin.
The presence of biotin is detected by incubation with streptavidin conjugated with Step 3: alkaline phosphatase.
Alkaline phosphatase catalyzes the hydrolysis of the substrate (4-Methyl-umbellifery) Step 4: phosphate) into a fluorescent product (4-Methyl-umbelifferone) the fluorescence of which is measured at 450 nm. The intensity of the fluorescence is proportional to the quantity of toxin A and/or toxin B present in the sample.

At the end of the VIDAS CDAB assay, results are automatically calculated by the VIDAS instrument. A test value as well as the qualitative result (positive, negative or equivocal) are provided on the result sheet for each sample.

E. Intended Use

VIDAS® C. difficile Toxin A & B (CDAB) assay is an automated test for use on the VIDAS instruments for the qualitative detection of Clostridium difficile toxin B in stool specimens using the ELFA technique (Enzyme-Linked Fluorescent Assay).

Item	Device[VIDAS CDAB]	Predicate[Premier Toxins A&B]
Intended Use	An automated test for use on the VIDASinstruments for the qualitative detection ofClostridium difficile toxin A and toxin B instool specimens using the ELFA technique(Enzyme-Linked Fluorescent Assay).	Same
Indications for Use	Interpretation of test results should bemade taking into consideration the patienthistory and any other tests performed.	Same
Specimen	Stool	Same
Assay Principle	Enzyme immunoassay	Same
Automated	Automated assay	Non-automated assay; requiresvisual and spectrophotometricdeterminations
Assay Technique	Enzyme-Linked Fluorescent Assay (ELFA)	Micro titer well assay
Antibodies	capture Anti-Toxin A (rabbit polyclonal)Anti-Toxin B (mouse monoclonal)	Anti-Toxin A (mouse monoclonal)Anti-Toxin B (goat polyclonal)
	detection Anti-Toxin A (mouse monoclonal)Anti-Toxin B (mouse monoclonal)	Anti-Toxin A (goat polyclonal)Anti-Toxin B (goat polyclonal)
Conjugate	Mouse monoclonal anti-toxin A and anti-toxin B antibodies conjugated with biotin	Horse-radish peroxidaseconjugated to anti-toxins

F. Technological Characteristics Summary

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1200 1100	nevice	redicate
Sample Volume	200 ul (liquid stool)200 mg (semi-solid & solid stools)	100 ul
Assav Time	~75 minutes	~95 minutes

G. Performance Data

A summary of the non-clinical and clinical test results is presented in the table below.

Item	Device[VIDAS CDAB]	Predicate[Premier Toxins A&B]
Non-clinical (Analytical) Comparison
Precision/Reproducibility	6 pools of samples tested in duplicate over6 daystotal precision: 7.4 – 37.6% CVinter-assay precision: 6.8 – 26.8% CVintra-assay precision: 2.9 – 26.3% CV	Samples tested in triplicatewithin run: 4.1 – 28.9% CVbtwn run: 6.2 – 31.7% CV
C. difficile strain types	A+/B+ 100% (23/23)A-/B+ 83% (15/18) 3 of the A-/B+ strains gave equivocalresults	A+/B+ 100% (25/25)A-/B+ 100% (3/3)
Limit of Detection (stool)	Toxin A at level of ≥ 7.73 ng/mL;Toxin B at level of ≥ 4.55 ng/mL	Toxin A at level of ≥ 1.4 ng/mL;Toxin B at level of ≥ 2.4 ng/mL
Clinical Studies Comparison
Number of specimen	1011 specimen	unknown
Study Site(s)	US and Europe	US
ResultsPositive Agreement:Negative Agreement:Global Agreement:	versus Predicate (all sites)81.3%; 95% CI: 73.4–87.6%99.5%; 95% CI: 98.8 – 99.9%97.1%; 95% CI: 95.9–98.1%	N/A

H. Conclusion

The VIDAS® CDAB Assay is substantially equivalent to the Meridian Premier Toxins A&B Assay.

The 510(k) summary includes only information that is also covered in the body of the 510(k). The summary does not contain any puffery or unsubstantiated labeling claims. The summary does not contain any raw data, i.e., contains only summary data. The summary does not contain any trade secret or confidential commercial information. The summary does not contain any patient identification information.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

DEC 2 1 2007

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Ms. Nikita S. Mapp Senior Regulatory Affairs Specialist bioMérieux, Inc. 595 Anglum Road Hazelwood, MO 63042

K072138 Re: Trade/Device Name: VIDAS® CDAB Regulation Number: 21 CFR 866.2660 Regulation Name: Microorganism differentiation and identification device Regulatory Class: Class I Product Code: LLH Dated: December 3, 2007 Received: December 5, 2007

Dear Ms. Mapp:

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 (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. 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 (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.

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 Parts 801 and 809); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).

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Page 2 -

This letter will allow you to begin marketing your device as described in your Section 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), please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at 240-276-0450. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding postmarket surveillance, please contact CDRH's Office of Surveillance and Biometric's (OSB's) Division of Postmarket Surveillance at 240-276-3474. For questions regarding the reporting of device adverse events (Medical Device Reporting (MDR)), please contact the Division of Surveillance Systems at 240-276-3464. You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (240) 276-3150 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.

Sincerely yours,

Sally attayna

Sally A. Hoivat. M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known): K072138

Device Name: VIDAS® C. difficile Toxin A & B (CDAB) Assay

Indications For Use: VIDAS® C. difficile Toxin A & B (CDAB) assay is an automated test for use on the VIDAS instruments for the qualitative detection of Clostridium difficile toxin A and toxin B in stool specimens using the ELFA technique (Enzyme-Linked Flurorescent Assay).

Prescription Use _ X (21 CFR Part 801 Subpart D) And/Or

Over the Counter Use _ (21 CFR Part 801 Subpart C)

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

Concurrence of CDRH, Office of In Vitro Diagnostic Device Evaluation and Safety (OVD)

Laudle M. Poole

Division Sign-Off Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) K072138

Regulation Number and Section

§ 866.2660 Microorganism differentiation and identification device.

(a)
Identification. A microorganism differentiation and identification device is a device intended for medical purposes that consists of one or more components, such as differential culture media, biochemical reagents, and paper discs or paper strips impregnated with test reagents, that are usually contained in individual compartments and used to differentiate and identify selected microorganisms. The device aids in the diagnosis of disease.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.