The C. DIFF QUIK CHEK COMPLETE™ test is a rapid membrane enzyme immunoassay for the simultaneous detection of Clostridium difficile glutamate dehydrogenase antigen and toxins A and B in a single reaction well. The test detects C. difficile antigen, glutamate dehydrogenase, as a screen for the presence of C. difficile and confirms the presence of toxigenic C. difficile by detecting toxins A and B in fecal specimens from persons suspected of having C. difficile disease. 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 COMPLETE™ test uses antibodies specific for qlutamate dehydrogenase (GDH) and Toxins A and B of C. difficile. The device contains a Reaction Window with two solid lines and a dotted line of immobilized antibodies. The Antigen line ("Ag") contains antibodies against C. difficile GDH. The Toxin line ("Tox") contains antibodies against C. difficile toxins A and B. The dotted line, representing a control line ("C"), contains anti-HRP antibodies. The Conjugate consists of antibodies to GDH, toxin A, and toxin B 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, toxin A or toxin B in the sample binds to the corresponding antibody-peroxidase conjugate. The antigen-antibody complexes migrate through a filter pad to a membrane where they are captured by the immobilized anti-GDH, anti-toxin A or Anti-toxin B antibody in the line. The Reaction Window is subsequently washed with Wash Buffer, followed by the addition of Substrate. After a 10-minute incubation, the "Ag" and "Tox" reaction is examined visually for the appearance of a blue line. A blue line indicates a positive test. A positive "C" reaction, indicated by a blue dotted 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 breakdown of the acceptance criteria and the study details for the C. DIFF QUIK CHEK COMPLETE™ device, based on the provided text:

Acceptance Criteria and Reported Device Performance

The document provides performance metrics rather than explicitly stated "acceptance criteria" in the format of pass/fail thresholds. However, the reported performance data can be interpreted as the device meeting the implicit acceptance criteria by demonstrating adequate clinical accuracy compared to established reference methods.

Metric (GDH Antigen)	Acceptance Criteria (Implicit)	Reported Device Performance (vs. Bacterial Culture)	Reported Device Performance (vs. Tissue Culture Assay – for positive samples)
Sensitivity	High (demonstrate effective detection of true positives)	90.5% (95% CI: 85.7 - 93.9)	N/A (compared differently)
Specificity	High (demonstrate effective identification of true negatives)	93.1% (95% CI: 91.2 - 94.7)	N/A (compared differently)
Predictive Positive Value	High (ensure positive results are reliable)	76.4% (95% CI: 70.7 - 81.3)	N/A (compared differently)
Predictive Negative Value	High (ensure negative results are reliable)	97.6% (95% CI: 96.2 - 98.4)	N/A (compared differently)
Correlation/Overall Agreement	High (demonstrate strong agreement with reference method)	92.6% (95% CI: 91.8 - 93.4)	90.1% (95% CI: 89.0 - 91.1)
Percent Positive Agreement	High (demonstrates agreement for positive results, especially against a gold standard for positive detection, like tissue culture for toxigenic C. difficile)	N/A (compared differently)	98.7% (95% CI: 95.0 - 99.8)
Percent Negative Agreement	High (demonstrates agreement for negative results)	N/A (compared differently)	88.8% (95% CI: 86.6 - 90.6)

Metric (Toxins A and B)	Acceptance Criteria (Implicit)	Reported Device Performance (vs. Tissue Culture Assay)
Sensitivity	High (demonstrate effective detection of true positives)	87.8% (95% CI: 81.4 - 92.3)
Specificity	High (demonstrate effective identification of true negatives)	99.4% (95% CI: 98.6 - 99.7)
Predictive Positive Value	High (ensure positive results are reliable)	95.8% (95% CI: 90.7 - 98.3)
Predictive Negative Value	High (ensure negative results are reliable)	98.1% (95% CI: 96.9 - 98.8)
Correlation	High (demonstrate strong agreement with reference method)	97.8% (95% CI: 97.6 - 98.0)

Study Information

Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size: n = 1126 clinical samples.
- Data Provenance: The study was conducted at 3 clinical sites. The document does not specify the country of origin, but given the FDA 510(k) submission, it is highly likely to be within the United States. The nature of comparing with "tissue culture assay" and "bacterial culture" suggests these are prospectively collected clinical samples, though the document does not explicitly state "prospective" or "retrospective." However, the wording "results from all 3 clinical sites are included in the summary" typically indicates a prospective collection for a clinical trial or evaluation.
Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
The document does not provide details on the number or qualifications of experts. However, the ground truth was established by laboratory methods (bacterial culture and tissue culture assay) and further resolved by commercial ELISA tests. These methods are typically performed by trained laboratory personnel.
Adjudication Method for the Test Set:
- GDH Antigen: Discrepant samples between the C. DIFF QUIK CHEK COMPLETE™ test and bacterial culture were resolved using the C. DIFFICILE CHEK™ - 60 ELISA (which detects GDH antigen).
- Toxins A and B: Discrepant results between the C. DIFF QUIK CHEK COMPLETE™ test and tissue culture assay were analyzed by either the C. DIFFICILE TOX A/B I/™ test or a "second commercially available Toxin A&B test."
If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done, What was the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance:
This device is a rapid membrane enzyme immunoassay (a diagnostic test kit), not an AI-powered image analysis or diagnostic system. Therefore, an MRMC comparative effectiveness study involving human readers with/without AI assistance is not applicable to this device. The results are read visually for the appearance of a blue line, which is a direct interpretation of the assay's chemical reaction, not a complex image requiring human expert interpretation in the way AI systems are typically evaluated in MRMC studies.
If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done:
Yes, a standalone performance was done. The results presented for sensitivity, specificity, predictive values, and agreement are directly comparing the device's output (positive/negative blue line) to the ground truth established by the reference methods (bacterial culture and tissue culture assay). There is no explicit "human-in-the-loop" aspect being evaluated in these performance metrics beyond the visual reading of the test result itself, which is integral to the device's function.
The Type of Ground Truth Used:
- For GDH antigen:
  - Primary reference: Bacterial Culture (for overall presence of C. difficile organism).
  - Secondary/Discrepant resolution: C. DIFFICILE CHEK™ - 60 ELISA (an established GDH antigen detection assay).
  - A separate comparison was also made against Tissue Culture Assay (presumably for toxigenic C. difficile, as it usually detects toxin production), specifically looking at the GDH antigen portion of the C. DIFF QUIK CHEK COMPLETE™.
- For Toxins A and B:
  - Primary reference: Tissue Culture Assay (the gold standard for detecting toxigenic C. difficile).
  - Secondary/Discrepant resolution: C. DIFFICILE TOX A/B I/™ test or a "second commercially available Toxin A&B test."
The Sample Size for the Training Set:
The document does not specify a separate "training set" size for the clinical accuracy evaluation. The n=1126 samples are referred to as the clinical performance evaluation set. This device is an immunoassay kit, which typically does not involve machine learning or AI algorithms that require distinct training and test sets in the same manner as software devices. Any "training" would have been part of the assay development and optimization phases, not explicitly quantified as a clinical "training set" in this context.
How the Ground Truth for the Training Set Was Established:
As there's no explicitly defined "training set" in the context of clinical accuracy for this type of device mentioned in the document, this question is not directly applicable. The methods used to establish ground truth for the evaluation set (bacterial culture and tissue culture assay with ELISA for discrepancy resolution) would be the standard reference methods used in the development and validation of similar assays.

Summary

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510(k) SUMMARY 7.

Contact Information	Charles PenningtonDirector of Product DevelopmentTECHLAB®, Inc.2001 Kraft DriveCorporate Research CenterBlacksburg, VA 24060Phone: 540-953-1664FAX: 540-953-1665Email: cpennington@techlab.com	MAR 2 6 2009
Date Prepared	August 28, 2008
Product and Trade Name	C. DIFF QUIK CHEK COMPLETE™
Classification	21 CFR 866.2660

Predicate Devices

For the detection of GDH antigen

C. difficile Culture Media such as cycloserine cefoxitin fructose agar (CCFA) is . available commercially from various sources.
C. DIFF QUIK CHEK® �
C. DIFF CHEK™ 60 ●
BD CULTURETTE™ CDT™ ◆
ImmunoCard® C. difficile EIA �

For the detection of Toxins A and B

C. DIFFICILE TOX-B TEST and C. difficile Toxin/Antitoxin along with human foreskin . monolayer tissue cultured cells (Diagnostic Hybrids, Inc.). Alternatively, clinical laboratories may use their own tissue cultured monolayer cells.
TOX A/B QUIK CHEK® �
C. DIFFICILE TOX A/B I™ .
Premier™ Toxins A&B .
ProSpecT® Clostridium difficile Toxin A/B .
ImmunoCard® Toxins A&B .
X/pect™ Clostridium difficile Toxin A/B .

For the simultaneous detection of GDH antigen and Toxin A

Biosite Triage® Micro Clostridium difficile Panel .

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Intended Use

The C. DIFF QUIK CHEK COMPLETE™ test is a rapid membrane enzyme immunoassay for the simultaneous detection of C. difficile glutamate dehydrogenase antigen and toxins A and B in a single reaction well. The test detects C. difficile antigen, glutamate dehydrogenase, as a screen for the presence of C. difficile and confirms the presence the toxigenic C. difficile by detecting toxins A and B in fecal specimens from persons suspected of having C. difficile disease. 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.

Device Description

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Comparative Information of Equivalent Devices For detection of GDH antigen:

Characteristics	510(k) Numbers	Intended Use	Format	Materials	TargetPopulation
C. difficileCacterial Culture	Usedbefore1976,510(k) notavailable.	Detection ofC. difficileorganism infecalspecimens	Bacterialculture	Specificselective media,CCFAa platesand CC BHIbbroth	Personssuspected ofhavingC. difficiledisease
C. DIFF CHEK TM- 60	K030992	Detection ofC. difficileorganism infecalspecimens	ELISA	Highly specificantibodiesagainstC. difficile GDH	Personssuspected ofhavingC. difficiledisease
BDCULTURETTETMCDTTM	K870864	Detection ofC. difficileorganism infecalspecimens	Latexagglutination	AntibodiesagainstC. difficile GDHand otherproteins	Personssuspected ofhavingC. difficiledisease
Triage® MicroC. difficile Panel,GDH portion	K974881	Detection ofC. difficileorganism infecalspecimens	Flow throughmembranetest	Highly specificantibodiesagainstC. difficile GDH	Personssuspected ofhavingC. difficiledisease
ImmunoCard®C. difficile EIA	K924979	Detection ofC. difficileorganism infecalspecimens	Lateral flowmembranetest	Highly specificantibodiesagainstC. difficile GDH	Personssuspected ofhavingC. difficiledisease
C. DIFF QUIKCHEK ® test	K053572	Detection ofC. difficileorganism infecalspecimens	Rapidmembrane	Highly specificantibodiesagainstC. difficile GDH	Personssuspected ofhavingC. difficiledisease
Characteristics	510(k) Numbers	Intended Use	Format	Materials	Target Population
Tissue culture assay (TOX-B TEST)	K935296	Detection of C. difficile toxin in fecal specimens	Tissue culture	Cell monolayer, specific neutralizing antiserum	Persons suspected of having C. difficile disease
C. DIFFICILE TOX A/B IITM	K003306 and K030404	Detection of C. difficile toxin in fecal specimens	Microassay ELISA	Highly specific antibodies against C. difficile toxins A and B	Persons suspected of having C. difficile disease
PremierTM Toxins A&B	K993914	Detection of C. difficile toxin in fecal specimens	Microassay ELISA	Highly specific antibodies against C. difficile toxins A and B	Persons suspected of having C. difficile disease
ProSpecT® Clostridium difficile Toxin A/B	K033479	Detection of C. difficile toxin in fecal specimens	Microassay ELISA	Highly specific antibodies against C. difficile toxins A and B	Persons suspected of having C. difficile disease
ImmunoCard® Toxins A&B	K041003	Detection of C. difficile toxin in fecal specimens	Rapid membrane	Highly specific antibodies against C. difficile toxins A and B	Persons suspected of having C. difficile disease
X/pectTM Clostridium difficile Toxin A/B	K041951	Detection of C. difficile toxin in fecal specimens	Rapid membrane	Highly specific antibodies against C. difficile toxins A and B	Persons suspected of having C. difficile disease
TOX A/B QUIK CHEK® test	K050891	Detection of C. difficile toxin in fecal specimens	Rapid membrane	Highly specific antibodies against C. difficile toxins A and B	Persons suspected of having C. difficile disease

a, CCFA, cycloserine - cefoxitin fructose agar plates

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

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For detection of toxins A and B:

· .

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Summary of Performance Data Clinical Accuracy For GDH antigen

The following tables show a summary of the clinical performance of the GDH antigen portion of the C. DIFF QUIK CHEK COMPLETE™ test. The discrepant samples generated from the C. DIFF QUIK CHEK COMPLETE™ and bacterial culture assay were resolved using the C. DIFFICILE CHEK™ - 60 ELISA, which detects GDH antigen. The protocols are presented in the Appendices. The results show that the C. DIFF QUIK CHEK COMPLETE™ test exhibited a correlation of 92.6% with bacterial culture.

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

n= 1126	Bacterial Culturepositive	Bacterial Culturenegative
C. DIFF QUIK CHEK COMPLETE™Antigen Line Positive	201	62
C. DIFF QUIK CHEK COMPLETE™Antigen Line Negative	21	842

		95% ConfidenceLimits
Sensitivity	90.5%	85.7 - 93.9
Specificity	93.1%	91.2 - 94.7
Predictive Positive Value	76.4%	70.7 - 81.3
Predictive Negative Value	97.6%	96.2 - 98.4
Correlation	92.6%	91.8 - 93.4

Twenty-nine of the 62 false positive samples were positive by the C. DIFF CHEK™ - 60 ELISA, and were considered true positives. Thirteen of the 21 false negative samples were negative by the ELISA, and were considered true negatives.

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Comparison of the GDH antigen portion to tissue culture assay

The following table shows a comparison of the GDH antigen portion of the C. DIFF QUIK CHEK COMPLETE™ test versus tissue culture assay. The protocols are presented in the Appendices. The results show that the C. DIFF QUIK CHEK COMPLETE™ test detected 98.7% of the tissue culture-positive samples.

Clinical Performance Comparing C. DIFF QUIK CHEK COMPLETE™ Test to Tissue Culture Assay

n= 1126	Tissue Culturepositive	Tissue Culturenegative
C. DIFF QUIK CHEK COMPLETE™Antigen Line Positive	154	109
C. DIFF QUIK CHEK COMPLETE™Antigen Line Negative	2	861

		95% ConfidenceLimits
Percent Positive Agreement	98.7%	95.0 - 99.8
Percent Negative Agreement	88.8%	86.6 - 90.6
Overall Percent Agreement	90.1%	89.0 - 91.1

Analytical Sensitivity

The cutoff for the assay was established at a concentration of 0.8 ng/mL for Glutamate Dehydrogenase.

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Summary of Performance Data Clinical Accuracy For Toxins A and B

The following tables show a summary of the clinical performance of the toxins A and B portion of the C. DIFF QUIK CHEK COMPLETE™ test. Results from all 3 clinical sites are included in the summary. Results from the C. DIFF QUIK CHEK COMPLETE™ were compared to tissue culture assay and discrepant results were analyzed by either the C. DIFFICILE TOX A/B I/™ test or a second commercially available Toxin A/B test. The results show that the C. DIFF QUIK CHEK COMPLETE™ test exhibited a sensitivity and specificity of 87,8% and 99,4%, respectively, compared to the tissue culture assay. The predictive positive and negative values were 95.8% and 98.1%, respectively, and the correlation was 97.8%.

Summary of clinical performance comparing the C. DIFF QUIK CHEK COMPLETE™ test versus tissue culture assay.

n= 1126	Tissue Culturepositive	Tissue Culturenegative
C. DIFF QUIK CHEK COMPLETE™Toxin Line Positive	137	6
C. DIFF QUIK CHEK COMPLETE™Toxin Line Negative	19	964

		95% ConfidenceLimits
Sensitivity	87.8%	81.4 - 92.3
Specificity	99.4%	98.6 - 99.7
Predictive Positive Value	95.8%	90.7 - 98.3
Predictive Negative Value	98.1%	96.9 - 98.8
Correlation	97.8%	97.6 - 98.0

Of the 6 tissue culture-negative/C. DIFF QUIK CHEK COMPLETE™-positive samples, 5 were positive in the C. DIFFICILE TOX A/B I/™ test. Of the 19 specimens that were tissue culture-positive/C. DIFF QUIK CHEK COMPLETE™-negative, 12 were neqative in the C. DIFFICILE TOX A/B I/™test or a second commercially available Toxin A&B test.

Analytical Sensitivity

The cutoff for the assay was established at concentrations of 0.63 ng/mL for toxin A and 0.16 ng/mL for toxin B.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/7/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is an abstract symbol that resembles a stylized caduceus, featuring a staff with three intertwined snakes and a pair of wings at the top.

Public Health Service

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Mr. Charles Pennington, MS Director of Product Development Techlab, Inc. 2001 Kraft Drive Blacksburg, VA 24060

Re: K082499

K062499
Trade/Device Name: C. DIFF QUIK CHEK COMPLETE™ Regulation Number: 21 CFR 866.2660 Regulation Name: Microorganism differentiation and identification device Regulatory Class: I Product Code: LLH Dated: November 5, 2008 Received: February 26, 2009

MAR 2 6 2009

Dear Mr. Pennington:

We have reviewed your Section 510(k) premarket notification of intent to market the we have formed your botton a 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 marketou in interblate ouments, 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 wint also provide of 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, provisions facturing 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 (1 will in the 20 base 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 i coderal agencies: "Found 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 vours.

Sally attaym

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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C. DIFF QUIK CHEK COMPLETE™ 510(k)

INDICATIONS FOR USE 2.

510(k) Number (if known):

K082499

C. DIFF QUIK CHEK COMPLETE™ Device Name:

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)

Fuedde leole

Division Sign-Off

Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) K082499

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.