Remel's ProSpecT® Clostridium difficile Toxin A/B Microplate Assay is a qualitative enzyme immunoassay (EIA) for the detection of C. difficile Toxin A and B in human fecal specimens from patients suspected of having Clostridium difficile disease. The test is intended for use as an aid in diagnosis of Clostridium difficile-associated disease (CDAD). For In vitro Diagnostic Use. Prescription Use.

Device Description

The ProSpecT® Clostridium difficile Toxin A/B test detects the presence of Toxin A and Toxin B in clinical stool specimens through the use of specific antibodies. Microwell strips are coated with mouse monoclonal anti-Toxin A and rabbit anti-Toxin B antibodies. A stool specimen is diluted in Sample Diluent or used directly if pre-diluted in modified Cary-Blair medium. The sample is added to a microwell allowing the toxins, if present, to bind to the immobilized antibodies. After washing to remove unbound components, a conjugate reagent containing goat anti-Toxin A-HRP and rabbit anti-Toxin B-HRP is added to each well. Unbound conjugate is removed by washing and a chromagenic substrate solution is added to detect the presence of bound toxin. A stop reagent is added and the test results are read visually or spectrophotometrically. The presence of a yellow color indicates the presence of toxin.

AI/ML Overview

Here's a summary of the acceptance criteria and study details for the ProSpecT® Clostridium difficile Toxin A/B Microplate Assay:

Acceptance Criteria and Device Performance

Metric	Acceptance Criteria (Implied)	Reported Device Performance (Dual Wavelength)	Reported Device Performance (Visual)
Sensitivity	Not explicitly stated (likely comparable to predicate or clinically acceptable for diagnostic aid)	90.3% (95% CI = 84.7% - 94.4%)	85.0% (95% CI = 76.5% - 91.4%)
Specificity	Not explicitly stated	96.2% (95% Cl = 94.3% - 97.5%)	95.5% (95% Cl = 93.2% - 97.1%)
Agreement (Visual vs. Dual Wavelength)	Not explicitly stated	99.0%	N/A

Note: The document does not explicitly state numerical acceptance criteria for sensitivity and specificity. However, the performance data presented, particularly the comparison to predicate devices, suggests that the device's performance met the FDA's requirements for substantial equivalence.

Study Details

Sample Size used for the test set and the data provenance:
- Dual Wavelength Test Set: 764 samples (165 positive, 599 negative based on CTA).
- Visual Interpretation Test Set: 586 samples (100 positive, 486 negative based on CTA).
- Data Provenance: Retrospective (clinical trial at three sites in the USA).
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The ground truth was established using the cellular cytotoxicity assay (CTA), which is a laboratory-based method. No human experts were involved in establishing the primary ground truth for the clinical samples.
Adjudication method for the test set:
- Not applicable as the ground truth was established by the cellular cytotoxicity assay (CTA), not human reviewers requiring adjudication.
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:
- No MRMC comparative effectiveness study was performed. This device is a qualitative enzyme immunoassay (EIA) for detecting C. difficile toxins, not an AI-powered diagnostic imaging or interpretation tool for human readers.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, the performance data provided (sensitivity and specificity for both dual wavelength and visual interpretation) represents the standalone performance of the ProSpecT® Clostridium difficile Toxin A/B Microplate Assay. The "visual interpretation" involves a human reading the color change, but it's the direct output of the assay itself, not an AI interpreting human input.
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The ground truth used was the cellular cytotoxicity assay (CTA), which is considered a gold standard for detecting C. difficile toxins.
The sample size for the training set:
- The document does not explicitly state a separate "training set" size. The reported performance is based on the clinical validation study. For an IVD like this, the development and optimization (which could be analogous to "training") would typically happen internally during the assay development phase, using characterized control samples and potentially a smaller set of clinical samples, but these are not typically referred to as a "training set" in the same way as for AI/ML models.
How the ground truth for the training set was established:
- Not explicitly described. For the general development of such assays, ground truth for sample characterization would be established using established laboratory methods, including the CTA for C. difficile toxins, and potentially molecular methods or culture.

Summary

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510(k) Summary

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

The assigned 510(k) number is: K033479.

A. Contact: David Teicher Remel Inc. Ramsey Operations 14000 Unity Street NW Ramsev. MN Phone: (763) 712-2367 Fax: (763) 323-7858 e-mail: dteicher@remel.com

Date of Preparation: January 19, 2004 B.

C. Name of Device and Classification

ProSpecT® Clostridium difficile Toxin A/B Microplate Assay Name: Classification: 866.2660 Reagents, Clostridium difficile toxin, Class I, LLH

D. Predicate Devices

Meridian Premier Toxins A&B:	510(k) K993914
Wampole C. difficile TOX A/B II:	510(k) K003306/K971182

E. Device Description

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Intended Use Statement F.

G. Device Comparison

ProductFeature	ProSpect®	Wampole	Merdian
Intended Use	Detection of C.difficile Toxins A andB in fecal specimens	Detection of C. difficileToxins A and B in fecalspecimens	Detection of C. difficileToxins A and B in fecalspecimens
Technology	EnzymeImmunoassay	Enzyme Immunoassay	Enzyme Immunoassay
CaptureAntibodies orMolecules:Device	Mouse monoclonalanti-Toxin A andrabbit anti-Toxin B	Polyclonal goatantibody against ToxinsA and B	Mouse monoclonal anti-Toxin A and polyclonalgoat anti-Toxin B
Antibodies:Conjugate	Goat anti-Toxin Aand rabbit anti-ToxinB	Toxin A monoclonalmouse antibody andToxin B polyclonal goatantibody	Polyclonal goat anti-Toxin A and anti-ToxinB
Material:Device	Microwell	Microwell	Microwell
Material:Conjugate	Horseradishperoxidaseconjugated to anti-toxins	Horseradish peroxidaseconjugated to anti-toxins	Horseradish peroxidaseconjugated to anti-toxins
SpecimenType	Fresh human stoolspecimens orspecimens inmodified Cary-Blair	Fresh human stoolspecimens	Fresh human stoolspecimens
Samplevolume	200 μl	50 μl	50 μl

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Summary of Performance Data H.

The performance of the ProSpecT® Clostridium difficile Toxin A/B Microplate Assay was evaluated in a clinical trial at three sites in the USA. The kit and predicate devices were compared to the cellular cytotoxicity assay (CTA).

Overall Performance:

Dual Wavelength (450/620-650 nm) Results:

Sensitivity: (149/165) x 100 = 90.3%; 95% CI = 84.7% - 94.4% Specificity: (576/599) x 100 = 96.2%; 95% Cl = 94.3% - 97.5%

		CTA Results
		+	-
ProSpecT® EIAResults (Dual)	+	149	23
	-	16	576
Total		165	599

Visual Interpretation of Test:

Sensitivity: (85/100) x 100 = 85.0%; 95% Cl = 76.5% - 91.4% Specificity: (464/486) x 100 = 95.5%; 95% Cl = 93.2% - 97.1%

	CTA Results
	+	-
ProSpecT® EIAVisual Results	85	22
-	15	464
Total	100	486

Percent Agreement: (580/586) x 100 = 99.0%

	ProSpecT® EIA ResultsOD 450/620-650
	+	-
ProSpecT® EIAVisual Results	104	3
-	3	476
Total	107	479

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EIA	Performance versus CTA
	Sensitivity		Specificity
	#	%	#	%
ProSpecT®*	33/40	82.5	263/268	98.1
Predicate 1	33/40	82.5	260/268	97.0
ProSpecT®	115/124	92.7	302/320	94.3
Predicate 2	98/124	79.0	309/320	96.5

Comparison to Predicate Devices:

Reproducibility l.

Reproducibility testing was conducted at three sites on three separate days with four blinded samples. Each site tested eight replicate wells of each specimen on each day of testing (n=288). The specimens included one negative specimen and three positive specimens with varying levels of reactivity. The average intra-assay coefficient of variation (CV) for a mid-range sample was 7.7%. The average inter-assay CV for a midrange sample was 18.9%.

Analytical Sensitivity J.

The ProSpecT® Clostridium difficile Toxin A/B Microplate Assay detects Toxin A at levels of >0.20 ng/ml and Toxin B at levels of ≥0.61 ng/ml.

Cross-Reactivity K.

Forty (40) microorganisms were evaluated with the ProSpecT® Clostridium difficile Toxin A/B Microplate Assay. Bacteria and yeast isolates were tested at ≥10° colony-forming units per ml (cfu/ml). Viral isolates were tested at concentrations of 104 TCIDso/ml (tissue culture infectious dose per milliliter). No cross-reactivity was observed. There was no cross-reactivity observed with Clostridium sordellii ATCC® 9714. However, published literature indicates that certain strains of C. sordellii can produce toxins which may be cross-reactive with antibodies to C. difficile Toxins A and B. The following organisms were tested in the ProSpecT® Clostridium difficile Toxin A/B Microplate Assay.

Organism	ATCC® designation
Aeromonas hydrophila	35654
Bacillus cereus	11778
Bacillus subtilis	6633
Bacteriodes fragilis	25285
Campylobacter coli	33559
Campylobacter jejuni	33291
Candida albicans	10231

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510(k) Submission Remel Inc. ProSpecT® Clostridium difficile Toxin A/B Microplate Assay

Organism	ATCC® designation
Clostridium beijerinckii (butyricum)	8260
Clostridium difficile (non-toxigenic)	700057
Clostridium haemolyticum	9650
Clostridium histolyticum	19401
Clostridium novyi (toxin A)	19402
Clostridium perfringens (Type A)	13124
Clostridium septicum	12464
Clostridium sordellii	9714
Clostridium sporogenes	19404
Clostridium tetani	19406
Enterobacter aerogenes	35028
Enterobacter cloacae	13047
Enterococcus faecalis	19433
Escherichia coli	11229
Klebsiella pneumoniae	13882
Peptostreptococcus anaerobius	27337
Porphyromonas asaccharolytica	25260
Proteus vulgaris	49132
Pseudomonas aeruginosa	27853
Salmonella choleraesuis (typhimurium)	23852
Serratia liquefaciens	27592
Shigella dysenteriae	11835
Shigella flexneri	12022
Shigella sonnei	25931
Staphylococcus aureus	25923
Staphylococcus aureus (Cowan)	12598
Staphylococcus epidermidis	12228
Vibrio cholerae	9459
Vibrio parahaemolyticus	17802
Yersinia enterocolitica	23715
Adenovirus type 40	VR-930
Adenovirus type 41	VR-931
Rotavirus (Complement fixation antigen)

Rotavirus (Complement fixation antigen)

Interfering Substances ட்ட

The following substances were tested with the ProSpecT® Clostridium difficile Toxin A/B Microplate Assay: Vancomycin (12.5 mg/ml), Metronidazole (12.5 mg/ml), blood, mucous, fecal fat, and the following over-the-counter anti-diarrheal products: Pepto-Bismol®, Imodium® A-D, and Kaopectate® (active ingredients: bismuth subsalicylate, loperamide HCl. and attapugite respectively). No interference with positive or negative specimens was observed.

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Image /page/5/Picture/1 description: The image shows the seal of the Department of Health & Human Services (HHS). The seal features an abstract design resembling an eagle or bird-like figure, with three stylized lines forming the body and wings. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" is arranged in a circular pattern around the central emblem.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

FEB 2 6 2004

Mr. David Teicher Manager Quality Systems and Regulatory Affairs Remel Inc. Ramsey Operation 14000 Unity Street NW Ramsey, MN 55303

K033479 Re:

Trade/Device Name: ProSpecT® C. difficile Toxin A/B Microplate Assay Regulation Number: 21 CFR 866.2660 Regulation Name: Microorganism differentiation and identification device Regulatory Class: Class I Product Code: LLH Dated: January 19, 2004 Received: January 20, 2004

Dear Mr. Teicher:

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 information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21CFR Part 807.97). 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 (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely yours,

Saqartys

Sally A. Hojvat, 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): K033479

Device Name: ProSpecT® C. difficile Toxin A/B Microplate Assay

Indications For Use:

For In vitro Diagnostic Use.

Prescription Use × (Part 21 CFR 801 Subpart D) AND/OR

Over-The-Counter Use (21 CFR 807 Subpart C)

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

Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD)

Luddi te Palo.

Division Sign-Off

Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) K033479

Page 1 of 1

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.