The C. DIFF QUIK CHEK™ test is a rapid membrane enzyme immunoassay for use as a screening test to detect Clostridium difficile antigen, glutamate dehydrogenase, in fecal specimens from persons suspected of having C. difficile disease. The test does not distinguish toxigenic from nontoxigenic strains of C. difficile. With the use of additional tests that detect C. difficile toxins, the test is to be used as an aid in the diagnosis of C. difficile disease. As with other C. difficile tests, results should be considered in conjunction with the patient history. FOR IN VITRO DIAGNOSTIC USE.

Device Description

The C. DIFF QUIK CHEK™ test uses antibodies specific for glutamate dehydrogenase (GDH) of C. difficile. The device contains a Reaction Window with two lines of immobilized antibodies. The test line ("T") contains antibodies against C. difficile GDH. The other, representing a control line ("C"), contains anti-IgG antibodies. The Conjugate consists of antibody to GDH coupled to horseradish peroxidase. To perform the test, the fecal specimen is diluted with Diluent, and Conjugate is added to the diluted sample. The diluted sample conjugate mixture is added to the Sample Well and the device is allowed to incubate at room temperature for 15 minutes. During the incubation, any GDH in the sample binds to antibodyperoxidase conjugate. The antigen-antibody complexes migrate through a filter pad to a membrane where they are captured by the immobilized anti-GDH antibody in the line. The Reaction Window is subsequently washed with Wash Buffer, followed by the addition of Substrate. After up to a 10-minute incubation, the "T" reaction is examined visually for the appearance of a blue line indicates a positive test. A positive "C" reaction, indicated by a blue line, confirms that sample and all reagents were added in proper sequence and volume, that reagents were active at the time of performing the assay, and that proper sample migration occurred.

AI/ML Overview

Here's a summary of the acceptance criteria and the study that proves the device meets them, based on the provided text:

Device: C. DIFF QUIK CHEK™ test

Intended Use: A rapid membrane enzyme immunoassay for use as a screening test to detect Clostridium difficile antigen, glutamate dehydrogenase, in fecal specimens from persons suspected of having C. difficile disease. The test does not distinguish toxigenic from nontoxigenic strains of C. difficile. With the use of additional tests that detect C. difficile toxins, the test is to be used as an aid in the diagnosis of C. difficile disease. Results should be considered in conjunction with the patient history.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are not explicitly stated as numerical targets in the document. However, the study aims to demonstrate substantial equivalence to previously cleared devices and clinical correlation. Based on the "Clinical Performance Comparing C. DIFF QUIK CHEK™ Test to Presumptive Bacterial Culture" table and the "Clinical Performance of C. DIFF QUIK CHEK™ Test versus Bacterial Culture Assay after Resolution by another GDH Test" table, the implied acceptance range would be within the 95% Confidence Limits of the reported performance metrics.

Performance Metric	Acceptance Criteria (Implied/Expected)	Reported Device Performance (vs. initial culture)	Reported Device Performance (vs. resolved culture)
Clinical Performance
Sensitivity	High sensitivity (e.g., >88%)	92.8% (95% CI: 88.3% - 95.7%)	N/A (not directly reported post-resolution)
Specificity	High specificity (e.g., >90%)	92.6% (95% CI: 90.4% - 94.3%)	N/A (not directly reported post-resolution)
Predictive Negative Value	High PVN (e.g., >96%)	97.8% (95% CI: 96.3% - 98.7%)	99.6% (95% CI: 98.7% - 99.9%)
Correlation	High correlation (e.g., >90%)	92.6% (95% CI: 91.7% - 93.4%)	96.9% (95% CI: 96.5% - 97.2%)
Analytical Sensitivity	Detect at low GDH concentration	Consistently positive at 0.4 ng/mL for GDH	Not applicable
Cross-Reactivity	No false positives with common organisms	No reactivity with listed organisms and viruses	Not applicable
Interfering Substances	No interference	No effect with listed substances	Not applicable
Reproducibility	High consistency (e.g., 100%)	100% correlation across 3 labs	Not applicable

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

Sample Size: 979 fecal specimens.
Data Provenance: The document states that "Results from 3 studies are included in the summary," and the protocols are in Appendix A and D. It does not specify the country of origin of the data or whether it was retrospective or prospective.

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

The document does not explicitly state the number or qualifications of experts used to establish initial ground truth. The primary comparator was "Presumptive Bacterial Culture."

4. Adjudication Method for the Test Set

The document describes an adjudication method for discrepant samples:

"The discrepant samples generated from the C. DIFF QUIK CHEK™ test and the presumptive bacterial culture assay were resolved using a PCR assay, an ELISA for the antigen, or a membrane test for the antigen, as described in the individual studies."
This indicates a "discrepant analysis" approach, where discrepancies between the index test (C. DIFF QUIK CHEK) and the initial comparator (presumptive bacterial culture) were sent for re-evaluation using one or more additional, often more sensitive or specific, methods (PCR, ELISA, membrane test).

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

No, a multi-reader, multi-case (MRMC) comparative effectiveness study was not done. This device is an in-vitro diagnostic test (a rapid membrane enzyme immunoassay) and not an AI-assisted diagnostic tool designed to aid human readers in interpreting images or other complex data. Therefore, the concept of human readers improving with AI assistance does not apply.

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

Yes, a standalone performance study was done. The C. DIFF QUIK CHEK™ test is presented as a standalone diagnostic device, where the visual interpretation of a distinct blue line (or lack thereof) is the final output. The performance metrics (sensitivity, specificity, etc.) presented are for the device operating independently.

7. The Type of Ground Truth Used

The primary initial ground truth was presumptive bacterial culture (Clostridium difficile Culture media such as cycloserine cefoxitin fructose agar (CCFA)).

For discrepant results, the refined ground truth was established using consensus or advanced methods including:

PCR assay
ELISA for the antigen
Another membrane test for the antigen

This is a form of resolved gold standard, where a more definitive test is used to resolve disagreements between the index test and the initial comparator.

8. The Sample Size for the Training Set

The document does not provide information regarding a specific "training set" or its sample size. This type of regulatory submission (510(k)) for an in-vitro diagnostic typically focuses on clinical validation of the final device, rather than the developmental or training phases that might involve machine learning algorithms. The development of an immunoassay involves laboratory optimization and verification, but not typically a "training set" in the context of AI.

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

As no specific training set information is provided, how its ground truth was established is not applicable and not described in this document.

Summary

{0}------------------------------------------------

Image /page/0/Picture/0 description: The image shows a handwritten string of characters, "K053572", in a bold, slightly irregular font. Below the string, there is a line of text that reads "C. DIFF QUIK CHEKTM 510(k)". The text is in a smaller, more formal font compared to the handwritten characters above it. The image appears to be a scan or a photograph of a document.

ារប្រព័ន

7. 510(k) SUMMARY

Contact Information	David M. LyerlyVice-President, Research & DevelopmentTECHLAB®, Inc.2001 Kraft DriveCorporate Research CenterBlacksburg, VA 24060Phone: 540-953-1664FAX: 540-953-1665Email: dlyerly@techlab.com
Date Prepared	December 20, 2005
Product and Trade Name	C. DIFF QUIK CHEKTM
Classification	21 CFR 866.2660

Predicate Devices

C. difficile Culture media such as cycloserine cefoxitin fructose agar (CCFA) is . available commercially from various sources.
C. DIFF CHEK™ -- 60 (K030992) TECHLAB®, Inc. (Blacksburg, VA) .
C. DIFF CHEK™ 30 (K030991) TECHLAB®, Inc. (Blacksburg, VA) .
BD CULTURETTE™ CDT™ (K870864) Becton, Dickinson and Company . (Franklin Lakes, NJ)
Triage® Micro Clostridium difficile Panel (K974881) Biosite Incorporated (San � Diego, CA)
ImmunoCard® C. difficile EIA (K924979) Meridian Bioscience, Inc. (Cincinnati, . OH)

Intended Use

Device Description

{1}------------------------------------------------

conjugate mixture is added to the Sample Well and the device is allowed to incubate at room temperature for 15 minutes. During the incubation, any GDH in the sample binds to antibodyperoxidase conjugate. The antigen-antibody complexes migrate through a filter pad to a membrane where they are captured by the immobilized anti-GDH antibody in the line. The Reaction Window is subsequently washed with Wash Buffer, followed by the addition of Substrate. After up to a 10-minute incubation, the "T" reaction is examined visually for the appearance of a blue line indicates a positive test. A positive "C" reaction, indicated by a blue line, confirms that sample and all reagents were added in proper sequence and volume, that reagents were active at the time of performing the assay, and that proper sample migration occurred.

Characteristics	510(k)Numbers	Intended Use	Format	Materials	TargetPopulation
C. DIFF QUIKCHEK™ test	Subject tothis 510(k)	Detection of C.difficile organismin fecalspecimens	Rapidmembrane	Highly specificantibodiesagainst C.difficile GDH	Personssuspected ofhaving C.difficile disease
C. difficilePresumptivebacterial culture	Used before1976,510(k) notavailable.	Detection of C.difficile organismin fecalspecimens	Bacterialculture	Specificselectivemedia, CCFAaplates and CCBHIb broth	Personssuspected ofhaving C.difficile disease
C. DIFF CHEK™- 60	K030992	Detection of C.difficile organismin fecalspecimens	ELISA	Highly specificantibodiesagainst C.difficile GDH	Personssuspected ofhaving C.difficile disease
C. DIFF CHEK™- 30	K030991	Detection of C.difficile organismin fecalspecimens	ELISA	Highly specificantibodiesagainst C.difficile GDH	Personssuspected ofhaving C.difficile disease
BDCULTURETTE™CDT™	K870864	Detection of C.difficile organismin fecalspecimens	Latexagglutination	Antibodiesagainst C.difficile GDHand otherproteins	Personssuspected ofhaving C.difficile disease
Triage® Micro C.difficile Panel,GDH portion	K974881	Detection of C.difficile organismin fecalspecimens	Flowthroughmembranetest	Highly specificantibodiesagainst C.difficile GDH	Personssuspected ofhaving C.difficile disease
ImmunoCard® C.difficile EIA	K924979	Detection of C.difficile organismin fecalspecimens	Lateral flowmembranetest	Highly specificantibodiesagainst C.difficile GDH	Personssuspected ofhaving C.difficile disease

Comparative Information of Equivalent Devices

a, CCFA, cycloserine - cefoxitin fructose agar plates

b, CC-BHI, cycloserine - cefoxitin brain-heart infusion liquid media

{2}------------------------------------------------

Summary of Performance Data Clinical Accuracy

The Tables below show a summary of the clinical performance of the C. DIFF QUIK CHEKTM test. Results from 3 studies are included in the summary. The discrepant samples generated from the C. DIFF QUIK CHEK™ test and the presumptive bacterial culture assay were resolved using a PCR assay, an ELISA for the antigen, or a membrane test for the antigen, as described in the individual studies. The protocols are included in Appendix A and D. The results show that the C. DIFF QUIK CHEK™ test exhibited a correlation of 92.6% with presumptive bacterial culture. When discrepant results were resolved by PCR, the correlation was 96.9%.

Clinical Performance Comparing C. DIFF QUIK CHEK™ Test to Presumptive Bacterial Culture

n=979	Presumptive BacterialCulture positive	Presumptive BacterialCulture negative
C. DIFF QUIK CHEKTM positive	206	56
C. DIFF QUIK CHEKTM negative	16	701

		95% Confidence Limits
Sensitivity	92.8%	88.3% - 95.7%
Specificity	92.6%	90.4% - 94.3%
Predictive Negative Value	97.8%	96.3% - 98.7%
Correlation	92.6%	91.7% - 93.4%

Twenty-nine of the 56 apparent false positive samples were positive by another GDH test, and were considered true positive. Twenty-seven remained false positive. Thirteen of the 16 apparent false negative samples were negative by another GDH test, and were considered true negative. Three remained false negative. The summary is presented below.

Clinical Performance of C. DIFF QUIK CHEK™ Test versus Bacterial Culture Assay after Resolution bv another GDH Test

n=979	Resolved BacterialCulture positive	Resolved BacterialCulture negative
C. DIFF QUIK CHEK™ positive	235	27
C. DIFF QUIK CHEK™ negative	3	714

		95% Confidence Limits
Predictive Negative Value	99.6%	98.7% - 99.9%
Correlation	96.9%	96.5% - 97.2%

Analytical Sensitivity

The test was consistently positive at a concentration of 0.4 ng/mL for GDH.

{3}------------------------------------------------

Cross-Reactivity

The specificity of the C. DIFF QUIK CHEK™ test was evaluated by examining the reactivity of a wide range of common intestinal bacteria and intestinal pathogens in the assay. For the analysis, the organisms were grown to early stationary phase (>10° CFU/ml). The I or the mary one, as comment in ids. The cultures were diluted in (i) fecal specimens that were negative for C. difficile (Negative Fecal Specimens) or (ii) fecal specimens that were spiked with toxigenic C. difficile cell filtrate to give a positive reaction (Positive Fecal Specimens). The latter specimens were evaluated to determine if any of the common intestinal bacteria and pathogens exhibited any deleterious effects on a positive reaction in the C. DIFF QUIK CHEK™ test. The fecal specimens then were diluted in Diluent and tested in the C. DIFF QUIK CHEK™ test.

Bacterium	Strain	Reaction innegative fecalspecimen	Reaction inpositive fecalspecimen
Aeromonas hydrophila	ATCC 7965	-	+
Bacillus cereus	ATCC 14579	-	+
Bacillus subtilis	ATCC 6051	-	+
Bacteroides fragilis	VPI 13785	-	+
Campylobacter coli	ATCC 49941	-	+
Campylobacter fetus	ATCC 25936	-	+
Campylobacter jejuni	ATCC 29428	-	+
Candida albicans	ATCC 10231	-	+
Clostridium bifermentans	VPI 2012	-	+
Clostridium butyricum	VPI 8260	-	+
Clostridium perfringens, type A	VPI 3624	-	+
Clostridium septicum	VPI 1524	-	+
Clostridium sordellii	VPI 9048	-	+
Clostridium sordellii	VPI 7319	-	+
Clostridium sporogenes	VPI 9743	-	+
Enterococcus faecalis	ATCC 19433	-	+
Escherichia coli EIEC	SD67	-	+
Escherichia coli	ATCC 25922	-	+
Escherichia coli O157 H7	B1409	-	+
Escherichia coli ETEC	E 2348169	-	+
Klebsiella pneumoniae	ATCC 9997	-	+
Peptostreptococcus anaerobius	ATCC 27337	-	+
Proteus vulgaris	ATCC 6380	-	+

A summary of the results is shown in the tables on the following pages. All of the organisms tested were negative in the C. difficile-negative fecal specimens and had no effect on the reaction with C. difficile-positive fecal specimens.

{4}------------------------------------------------

Bacterium	Strain	Reaction innegative fecalspecimen	Reaction inpositive fecalspecimen
Salmonella typhimurium	ATCC 14029	-	+
Shigella dysenteriae	ATCC 12022	-	+
Shigella flexneri	ATCC 12122	-	+
Shigella sonnei	ATCC 11060	-	+
Staphylococcus aureus	ATCC 6358	-	+
Staphylococcus aureus (Cowans)	ATCC 12598	-	+
Staphylococcus epidermidis	VPI 13140	-	+
Vibrio parahaemolyticus	ATCC 17802	-	+
Yersinia enterocolitica	ATCC 9610	-	+

Culture fluids containing viruses were used as provided by the American Type Culture Collection. Each was diluted ca. 1:20 in the kit Diluent and tested according to the Package Insert. The titer of the fluids is shown in the table below.

Virus	TCID50 units(per 0.2 mL)	ATCC#	Reaction innegative fecal	Reaction inpositive fecal
Adenovirus type 1	104.5	VR-1	-	+
Adenovirus type 2	106.5	VR-846	-	+
Adenovirus type 3	108.25	VR-3	-	+
Adenovirus type 5	106.75	VR-5	-	+
Adenovirus type 40	104.5	VR-931	-	+
Adenovirus type 41	104.5	VR-930	-	+
Human coronavirus	103.5	VR-740	-	+
Coxsackievirus B2	105.75	VR-29	-	+
Coxsackievirus B3	105	VR-30	-	+
Coxsackievirus B4	104.75	VR-184	-	+
Coxsackievirus B5	107.5	VR-185	-	+
Echovirus 9	104.5	VR-1050	-	+
Echovirus 11	105	VR-1052	-	+
Echovirus 18	104	VR-48	-	+
Echovirus 22	103.3	VR-1063	-	+
Echovirus 33	105	VR-582	-	+
Enterovirus type 68	106	VR-1076	-	+
Enterovirus type 69	104.3	VR-1077	-	+
Enterovirus type 70	105.5	VR-836	-	+
Enterovirus type 71	pending	VR-784	-	+

{5}------------------------------------------------

Interfering Substances

The following substances had no effect on test results, either with C. difficile-negative or C. difficile-positive fecal specimens, when present in fecal material in the concentrations indicated in the table.

Substance	Concentration	Reaction innegative fecalspecimen	Reaction inpositive fecalspecimen
Hog gastric mucin	3.5% w/v	-	+
Human blood (O, Rh-)	40% v/v	-	+
Barium sulfate	5% w/v	-	+
Imodium®	5% w/v	-	+
Kaopectate®	5 mg/ml	-	+
Pepto-Bismol®	5% w/v	-	+
Steric/palmitic acid (fecal fats)	40% w/v	-	+
Metronidazole	0.25% w/v	-	+
Vancomycin	0.25% w/v	-	+

Reproducibility

A total of 8 fecal specimens, 6 positive and 2 negative, were coded to prevent identification and were sent to each of three independent laboratories for analysis using the C. DIFF QUIK CHEK™ test. The results from each laboratory were compared with in-house results. The results were consistent among the different locations, and exhibited a correlation of 100%. The positive specimens were confirmed to be positive and the negative specimens were confirmed to be negative at all sites using the C. DIFF QUIK CHEKTM test.

{6}------------------------------------------------

8. REFERENCES

1. Bartlett JG. 1990. Clostridium difficile: clinical considerations. Rev. Infect. Dis. 12:S243-51
1. Bartlett JG. 1998. Clostridium difficile Associated diarrhea and colitis. In Infectious Diseases, 2nd Ed., (eds) Gorbach SL, Bartlett JG, and Blacklow NR, W.B. Saunders Company, Philadelphia, London, Toronto, Montreal, Sydney, Tokyo
1. Lyerly DM, Wilkins TD. 1995. Clostridium difficile. In Infections of the Gastrointestinal Tract (eds) Blaser MJ, Smith PD, Ravdin JI, Greenberg HB, and Guerrant RL Raven Press, Ltd., New York, pp 867-91
1. Lyerly DM, Neville LM, Evans DT, Fill J, Allen S, Greene W, Sautter R, Hnatuck P, Torpey D. Schwalbe R. 1998. Multicenter evaluation of the Clostridium difficile TOX A/B TEST. J. Clin. Microbiol. 36:184-90
1. Kato H, Kato N, Watanabe K, Iwai N, Nakamura H, Yamamoto T, Suzuki K, Kim S-M, Chong Y, Wasito EB. 1998. Identification of toxin A-negative, toxin B-positive Clostridium difficile by PCR. J. Clin. Microbiol. 36:2178-82
1. Alfa MJ, Kabani A, Lyerly D, Moncrief S, Neville LM, Al-Barrak A, Harding GK, Dyck B, Olekson K, Embil JM. 2000. Characterization of a toxin A-negative, toxin B-positive strain of Clostridium difficile responsible for a nosocomial outbreak of Clostridium difficileassociated diarrhea. J. Clin. Microbiol. 38:2706-14
1. Kraft D. 1999. Personal communications.
1. Kato H, Kato N, Katow S, Maegawa T, Nakamura S, Lyerly DM. 1999. Deletion in the repeating sequences of toxin A gene of toxin A-negative, toxin B-positive Clostridium difficile strains. FEMS Microbiol. Lett. 175:197-203
1. Moncrief JS, Zheng L, Neville LM, Lyerly DM. 2000. Genetic characterization of toxin Anegative, toxin B-positive Clostridium difficile isolates by PCR. J. Clin. Microbiol. 38:3072-5
1. von Eichel-Streiber C, Zec-Pirnat I, Grabnar M, Rupnik M. 1999. A nonsense mutation abrogates production of a functional enterotoxin A in Clostridium difficile toxinotype VIII strains of serogroups F and X. FEMS Microb. Lett. 178:163-8
1. Fluit AC, Wolfhagen MJHM, Verdonk GPHT, Jansze M, Torensma R, Verhoef J. 1991. Nontoxigenic strains of Clostridium difficile lack the genes for both toxin A and toxin B. J. Clin. Microbiol. 29:2666-7
1. Anderson BM, Anderson CD, Van Tassell RL, Lyerly DM, Wilkins TD. 1993. Purification and characterization of Clostridium difficile glutamate dehydrogenase. Archives Biochem. Biophy. 300:483-8
1. Lyerly DM, Barroso LA, Wilkins TD. 1991. Identification of the latex test-reactive protein of Clostridium difficile as glutamate dehydrogenase. J. Clin. Microbiol. 29:2639-42
1. Miles BL, Siders JA, Allen SD. 1988. Evaluation of a commercial latex test for Clostridium difficile for reactivity with C. difficile and cross-reactions with other bacteria. J. Clin. Microbiol. 26:2452-5
1. Lyerly DM, Ball DW, Toth J, Wilkins TD. 1988. Characterization of cross-reactive proteins detected by Culturette Brand Rapid Latex Test for Clostridium difficile. J. Clin. Microbiol. 26:397-400
1. Landry ML, Topal J, Ferguson D, Giudetti D, Tang Y. 2001. Evaluation of Biosite Triage Clostridium difficile panel for rapid detection of Clostridium difficile in stool samples. J. Clin. Microbiol 39:1855-8

{7}------------------------------------------------

1. Alfa MJ, Swan B, VanDekerkhove B, Pang P, Harding GK. 2002. The diagnosis of Clostridium difficile-associated diarrhea: comparison of Triage C. difficile panel, EIA for Tox A/B and cytotoxin assays. Diagn. Microbiol. Infect. Dis 43:257-63
1. Turgeon DK, Novicki TJ, Quick J, Carlson L, Miller P, Ulness B, Cent A, Ashley R, Larson A, Coyle M, Limaye AP, Cookson BT, Fritsche TR. 2003. Six Rapid Tests for Direct Detection of Clostridium difficile and Its Toxins in Fecal Samples Compared with the Fibroblast Cytotoxicity Assay. J. Clin. Microbiol. 41:667-70
1. Gumerlock PH, Tang YJ, Meyers FJ, Silva J, Jr. 1991. Use of the polymerase chain reaction for the specific and direct detection of Clostridium difficile in human feces. Rev. Infect. Dis. 13:1053- 60
1. Gumerlock PH, Tang YJ, Weiss JB, Silva J, Jr. 1993. Specific detection of toxigenic strains of Clostridium difficile in stool specimens. J. Clin. Microbiol. 31:507-11
1. Boondeekhun HS, Gurtler V, Odd ML, Wilson VA, Mayall BC. 1993. Detection of Clostridium difficile enterotoxin gene in clinical specimens by the polymerase chain reaction. J. Med. Microbiol. 38:385-7
1. Lou Q, Chong SKF, Fitzgerald JF, Siders JA, Allen SD, and Lee C-H. 1997. Rapid and effective method for preparation of fecal specimens for PCR assays. J. Clin. Microbiol. 35:281-3
1. Kato N, Ou C-Y, Kato H, Bartley SL, Luo C-C, Killgore G.E, and Ueno K. 1993. Detection of toxigenic Clostridium difficile in stool specimens by the polymerase chain reaction. J. Infect. Dis. 167:455-8
1. Rupnik M, Avesani V, Janc M, von Eichel-Streiber C, Delmee M. 1998. A novel toxinotyping scheme and correlation of toxinotypes with serogroups of Clostridium difficile isolates. J. Clin. Microbiol. 36:2240-7
1. Bélanger SD, Biossinot M, Clairoux N, Picard FJ, Bergeron MG. 2003. Rapid detection of Clostridium difficile in feces by real-time PCR. J. Clin. Microbiol. 41:730-4
1. Guilbault C, Labbe A-C, Poirier L, Busque L, Beliveau C Laverdiere M. 2002. Development and evaluation of a PCR method for detection of the Clostridium difficile toxin B gene in stool specimens. J. Clin. Microbiol. 40:2288-90
1. Wolfhagen MJHM, Fluit AC, Torensma R, Poppelier MJJG, Verhoef J. 1994. Rapid detection of toxigenic Clostridium difficile in fecal samples by magnetic immuno PCR assay. J. Clin. Microbiol. 32:1629-33
1. Summanen P, Baron EJ, Citron DM, Strong C, Wexler HM, Fingold SM, Wadsworth Anaerobic Bacteriology Manual, Fifth Edition. 1993. Star publishing company, Belmont, California
1. Zheng L, Keller SF, Lyerly DM, Carman RJ, Genheimer CW, Gleaves CA, Kohlhepp SJ, Young S, Perez S, Ye K (2004) Multicenter Evaluation of a New Screening Test that Detects Clostridium difficile in Fecal Specimens. J. Clin. Microbiol. 42:3837-3840

{8}------------------------------------------------

Image /page/8/Picture/1 description: The image shows the seal of the U.S. Department of Health & Human Services. The seal is circular and contains the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the top half of the circle. In the center of the seal is an abstract image of an eagle.

3 2006 NOV

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

David M. Lyerly, Ph.D. Vice President of Research and Development TECHLAB®, Inc. 2001 Kraft Drive Blacksburg, VA 24060-6358

Re: K053572

Trade/Device Name: C. DIFF QUIK CHEK™ Regulation Number: 21 CFR 866.2660 Regulation Name: Microorganism Differentiation and Identification Device Regulatory Class: Class I Product Code: MCB Dated: March 29, 2006 Received: March 30, 2006

Dear Dr. Lyerly:

This letter corrects our substantially equivalent letter of April 26, 2006.

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 (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 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.

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); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (sections 531-542 of the Act); 21 CFR 1000-1050.

{9}------------------------------------------------

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 (240)276-0450. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). Other general information on your responsibilities under the Act may be obtained 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,

Sally, autogra

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

{10}------------------------------------------------

Indications for Use

510(k) Number (if known): K053572

C. DIFF QUIK CHEK TM Device Name:

Indications For Use: The C. DIFF QUIK CHEK™ test is a rapid membrane enzyme immunoassay for use as a screening test to detect Clostridium difficile antigen, glutamate dehydrogenase, in fecal specimens from persons suspected of having C. difficile disease. The test does not distinguish toxigenic from nontoxigenic strains of C. difficile. With the use of additional tests that detect C. difficile toxins, the test is to be used as an aid in the diagnosis of C. difficile disease. As with other C. difficile tests, results should be considered in conjunction with the patient history.

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)

Ludella T. Park

Page 1

vision Sien- M

Office of the Vitro Diagnosic Device Evaluation and Safer

K05 3572

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.