The BioStar® CdTOX A OlA assay is an Optical ImmunoAssay test for the rapid qualitative detection of Clostridium difficile Toxin A in human fecal samples from patients suspected of having Clostridium difficile associated disease (CDAD). This test is intended for in vitro diagnostic use as an aid in the diagnosis of CDAD.

Device Description

The CdTOX A OIA test involves the qualitative detection of the enterctoxin (Toxin A) produced by Clostridium difficile. The Optical Immuno Assay technology enables the direction of a physical change in the optical thickness of molecular this change is a result of antigen-antibody binding on an optical surface (silicon wafer). When a sample containing Toxin A (antigen) from Clostridium difficile is placed directly on the optical surface, the immobilized specific antibody captures the antigen. After washing, the substrate is added, increasing the thickness (Mass Enhancement) of the molecular thin film. This change in thickness alters the reflected light path and is visually perceived as a color changes in optical thickness produce a distinct, visible color change. A positive result appears as a purple spot on the predominant gold background. When antigen is not present in the specimen, no binding takes place. Therefore, the optical thickness remains unchanged and the surface retains the original gold color indicating a negative result.

AI/ML Overview

The provided text describes the acceptance criteria and the study that proves the device meets those criteria for the BioStar® CdTOX A OIA® assay.

Here's a breakdown of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" as a separate list with specific numerical targets for all metrics. However, it presents analytical and clinical performance data in comparison to a predicate device and a reference method (cytotoxicity assay), implying these are the metrics against which the device's performance is judged. The primary comparison is often to demonstrate substantial equivalence to the predicate device and acceptable performance against a gold standard (cytotoxicity assay).

Metric / Criterion	Reported Device Performance (CdTOX A OIA)	Comparative Performance (Predicate Device - Premier EIA)	Reference Method Performance (Cytotoxicity Assay - CTA)
Analytical Sensitivity (Limit of Detection)
Buffer Control	3 ng/g	Not specified	Not specified
Liquid Stool	3-8 ng/g	Not specified	Not specified
Semi-Solid Stool	4-8 ng/g	Not specified	Not specified
Formed Stool	3-5 ng/g	Not specified	Not specified
Analytical Specificity (Cross Reactivity)
Microorganisms tested	No reactivity or interference observed.	Not specified	Not specified
Cryptosporidium parvum and Giardia lamblia	No reactivity or interference observed.	Not specified	Not specified
Interfering Substances
Whole blood, RBC, WBC, mucous, barium sulfate	Did not interfere.	Not specified	Not specified
Toxin Stability	Sufficiently stable.	Not specified	Not specified
Reproducibility (Hospital Labs)	94.4% (85/90) overall	Not specified	Not specified
Reproducibility (Artificial Stool Matrix Study - Hospitals)	97.5% (117/120)	Not specified	Not specified
Reproducibility (Artificial Stool Matrix Study - POLs)	97.8% (88/90)	Not specified	Not specified
Reproducibility (Overall Artificial Stool Matrix Study)	97.6% (205/210)	Not specified	Not specified
Clinical Sensitivity (vs. CTA)	77.3%	81.8%	100% (as the reference)
Clinical Specificity (vs. CTA)	93.8%	92.0%	100% (as the reference)
Clinical Concordance (vs. CTA)	91.0%	90.3%	100% (as the reference)
Concordance (vs. Premier EIA)	95.0% (98+/+, 684 -/-)	100% (as the reference)	Not applicable
Discordance (vs. Premier EIA)	5.0% (19 +/-, 22 -/+)	0% (as the reference)	Not applicable

2. Sample size used for the test set and the data provenance:

Analytical Sensitivity: No specific sample size is given for the "test set" in the traditional sense. It involved adding known concentrations of Toxin A to five specimens each of liquid, semi-solid, and solid stools, tested in duplicate.
Analytical Specificity (Cross Reactivity) & Interfering Substances: Microorganisms grown to ~1.0 X 10 cfu/mL or greater; Cryptosporidium parvum and Giardia lamblia rested at 1.25 X 10^6 cysts for cross-reactivity. For interfering substances, whole blood, RBC, WBC, mucous (25mg/g), and barium sulfate (58% w/w suspension) were tested. The number of specimens tested with interfering substances is not explicitly stated.
Reproducibility:
- Three hospital laboratories study: 10 blinded samples tested at each site at three separate times. Total: 10 samples * 3 sites * 3 times = 90 tests.
- Artificial stool matrix study (four hospital labs and three physician office labs): Comparable samples prepared and tested. Total: 210 tests.
Clinical Sensitivity and Specificity (vs. CTA): A study performed at a central hospital lab. Number of samples used for this specific comparison is not explicitly stated.
Clinical Performance Evaluation (versus Premier EIA): 874 specimens.
Data Provenance:
- Clinical Sensitivity and Specificity (vs. CTA): "a central hospital lab."
- Clinical Performance Evaluation (versus Premier EIA): "four clinical trial sites (central hospital labs) located in the Southwest, Mid-Atlantic and East Coast regions of the United States."
- Reproducibility: "three hospital laboratories" and "four hospital laboratories and three physician office laboratories (POLs)".
- All clinical samples were "from patients suspected of having or with a history of CDAD." The clinical studies appear to be retrospective as samples were "submitted for C. difficile testing on the basis of clinical history of the patient."

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

The document does not explicitly mention the number or qualifications of experts used to establish the ground truth.

4. Adjudication method for the test set:

The document does not describe an adjudication method for the test set.

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 as the device is a diagnostic assay (in vitro diagnostic device) for detecting a toxin, not an AI-assisted imaging or interpretation device that would involve human readers.

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

The device (CdTOX A OIA) itself is a standalone assay. It's a chemical test ("Optical ImmunoAssay technology") that provides a visual result ("A positive result appears as a purple spot on the predominant gold background"). There is no "algorithm" or human-in-the-loop interpretation beyond visual inspection of the color change, which is inherent to the test's design. The clinical studies evaluated the performance of this standalone assay.

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

For the clinical sensitivity and specificity evaluation, the cytotoxicity assay (CTA) was used as the ground truth.
For the comparison with the predicate device, the Premier EIA (another commercial immunoassay) was used as a comparative method, not strictly a ground truth, although concordance was evaluated against it.

8. The sample size for the training set:

The document does not explicitly mention a "training set" in the context of machine learning or algorithm development. The development and analytical testing of an in vitro diagnostic device typically involve iterative design and optimization, but not in the same way as training a machine learning model.

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

As no explicit "training set" in a machine learning context is mentioned, this question is not applicable. The device's development likely relied on established biochemical principles and extensive internal analytical validation using spiked samples and characterization, rather than a separate training set with ground truth labels.

Summary

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

NOV - 2 1999

8.0 510(k) SUMMARY (page 1 of 4)

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: _ K991829

A. Safety and effectiveness information required per [5807.92(a)(1)]:

SUBMITTER'S NAME: BioStar, Inc. .
ADDRESS: 6655 Lookout Rd. Boulder, CO 80301 .
TELEPHONE: (303) 530-3888 ext. 659 .
. FAX: (303) 530-6601
CONTACT PERSON: Curtis A. Carlson .
DATE 510(k) SUMMARY PREPARED: May 28, 1999; revised October 27, 1999. ●

B. Safety and effectiveness information required per [$807.92(a)(2)]:

TRADE OR PROPRIETARY NAME: CATOX A OLA® .
. COMMON NAME: C. difficile Toxin A Assay
CLASSIFICATION NAME: Direct Antigen Detection Assay, Clostridium difficile .

C. Identification of legally marketed device to which we are claiming equivalence [§807.92(a)(3)]:

TRADE OR PROPRIETARY NAME: PREMIER™ C. difficile Toxin A ●
. REGULATORY CLASS: Class I
PRODUCT CODE: 83LLH .
MANUFACTURER: Meridian Diagnostics, Inc. .
510(k) NUMBER: K903456 ●

Note: Performance of the CdTOX A OIA product was also established versus cytotoxicity assay.

D. Description of device [§807.92(a)(4)]:

Principle of the Test:

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

Biostar CdTOX A OLA 510(k) Summary. Revised October 27, 1999

8.0 510(k) SUMMARY (page 2 of 4)

Device Components:

The CdTOX A OLA test kit contains the following:

Reaction Tubes Reagent 1: Conjugate Wash Solution Substrate Test Devices Positive Control Negative Control Transfer Pipettes Sampling Brushes

E. Intended use of device [§807.92(a)(5)]:
The BioStar® CdTOX A OlA assay is an Optical ImmunoAssay test for the rapid qualitative detection of Clostridium difficile Toxin A in human fecal samples from patients suspected of having Clostridium difficile associated disease (CDAD). This test is intended for in vitro diagnostic use as an aid in the diagnosis of CDAD.

F. Technological characteristics [§807.92(a)(6)]:

Technological Characteristic	Predicate Device (Premier TM Toxin A)	Our Device (CdTOX A OLA)
Intended Use	The PremierTM C. difficile Toxin A assay isan Enzyme Immunoassay for the Detectionof C. difficile Toxin A in Stool Specimen.	The BioStar® CdTOX A OIA assay isan Optical ImmunoAssay test for therapid qualitative detection ofClostridium difficile Toxin A inhuman fecal samples from patientssuspected of having Clostridiumdifficile associated disease (CDAD).This test is intended for in vitrodiagnostic use as an aid in thediagnosis of CDAD.
Detection	Detects C. difficile Toxin A	Detects C. difficile Toxin A
Technology	Enzyme Immunoassay (EIA) Microwell	Optical Immunoassay (OIA)
Specimens Evaluated	Stool	Stool

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

8.0 510(k) SUMMARY (page 3 of 4)

G. Summary of nonclinical testing [§807.92(b)(1)]:

Analytical Sensitivity:

The analytical sensitivity was determined by adding known concentrations of Toxin A to five specimens each of liquid, semi-solid, and solid stools. Seeded specimens were tested in duplicate by the CdTOX A OfA test. Results are summarized in the table below.

Limit of Detection by Stool Type

Toxin A Seeded Matrix	Limit of Detection (ng/g)
Buffer Control	3
Liquid Stool	3-8
Semi-Solid Stool	4-8
Formed Stool	3-5

Analytical Specificity (Cross Reactivity):

To determine the analytical specificity of the CdTOX A OIA test, microorganisms were grown on the appropriate media and suspended to a concentration of approximately 1.0 X 10 cfu/mL or greater and tested in the absence and presence of Toxin A near the lower limit of detection of the assay. . Cryptosporidium parvum and Giardia lamblia were rested at 1.25 X 10° cysts reactivity or interference was observed.

Interfering Substances:

Interference testing was performed to determine the effect of substances which might be encountered in the collection of specimens. Whole blood, Red Blood Cells (RBC), White Blood Cells (WBC), mucous (25mg/g), and barium sulfate (58% w/w suspension) were tested and did not interfere with the CdTOX A OLA test. All assays were run per the procedure described in the package insert.

Sample/Toxin Stability

Toxin stability in liquid, semi-solid, and formed stool was judged by spiking Toxin A (Lee Laboratories) at levels near the analytical sensitivity of the assay and testing at the specified times. Spiked samples were initially held at room temperature for 2 hours then transferred to 2-8℃ storage. These results show that over the sample consistency types tested, the toxin is sufficiently stable to allow detection in samples handled as recommended in the package insert.

Stool Consistency Reactivity:

The reactivity of stools with liquid, semi-solid, or formed consistency was evaluated using the OdTOX A OIA test and microwell EIA test. The positivity rates were similar for the two assays across all three types of stool specimens. All of the specimens in the clinical performance evaluation of the CdTOX A OLA rest were submitted for C. difficile testing on the basis of clinical history of the patient, not the consistency of the specimen. Test results are illustrated in the table below.

Reactivity Data From Four Clinical Sites

Stool Consistency

	Liquid (445)	Semi-solid (298)	Formed (80)
CdTOX A OIA +	42 (9%)	54 (18%)	21 (26%)
EIA +	51 (11%)	50 (17%)	19 (24%)

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

8.0 510(k) SUMMARY (page 4 of 4)

Summary of clinical testing [§807.92(b)(2)]: H.

Reproducibility

Reproducibility testing was conducted using a stool marix at three hospital laboratories. Ten blinded samples were tested at each site at three separate times. Samples consisted of negative, low, and moderate levels of C. difficile Toxin A. The concentration of toxin in the low samples was less than 2-fold over the minimum detectable limit. The overall reproducibility was 94.4% (85/90). An additional study was done using artificial stool matrix. Comparable samples were prepared and tested at four hospital laboratories and three physician office laboratories (POLs). Overall reproducibility in this study was 97.6% (205/210); at the hospitals, 97.5% (117/120) at the POLs, 97.8% (88/90).

Clincal Sensitivity and Specificity

A sudy comparing the CdTOX A OIA test and a commercial microwell immunoassay, the Premier EIA, to cytotoxicity assay (CTA) was performed at a central hospital lab. The sensitivity, specificity, and concordance of the CdTOX A OIA test was 77.3%, 93.8%, and 91.0% respectively. The sensitivity, specificity, and concordance of the Premier ELA test was 81.8%, 92.0%, and 90.3% respectively.

The CdTOX A OIA test was evaluated versus the Premier EIA at four clinical trial sites (central hospital labs) located in the Southwest, Mid-Atlantic and East Coast regions of the United States. A total of 874 specimens from patients suspected of having or with a history of CDAD were evaluated by the CdTOX A OLA test and the Premier ELA. Of these, 823 gave unequivocal results using the BlA method. Concordance between the Cd TOX A OlA test and the Premier EIA test was 95.0% (98+/+, 684 -/-); discordance was 5.0% (19 +/-, 22 -/+).

I. Conclusions from nonclinical / clinical testing [§807.92(b)(3)]:
The results of the above described internal and external studies demonstrate that the CdTOX A OLA test is as safe and effective as the cleared predicate device.

No additional information has been requested by FDA at this time.

J. Additional information [§807.92(d)]:

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

Image /page/4/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features a stylized eagle with three lines forming its body and two wavy lines representing its legs. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA" are arranged in a circular pattern around the eagle.

NOV - 2 1999

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Curtis A. Carlson, Ph.D. Director, Regulatory Affairs BioStar, Inc. 6655 Lookout Road Boulder, Colorado 80301

Re: K991829 Trade Name: CdTOX A OIA® Test Kit Regulatory Class: I Product Code: LLH Dated: October 7, 1999 Received: October 8, 1999

Dear Dr. Carlson:

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 (QS) 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.

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

Page 2

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 vours.

Steven Butman

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

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

INDICATIONS FOR USE STATEMENT

510(k) Number (if known):	K991829
Device Name:	CdTOX A OIA®

Indications For Use:

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

Concurrence of CDRH, Qffice of Device Evaluation (ODE)

Woody Dubois

(Division Sign-Off) Division of Clinical Laboratory Devices K991829 510(k) Number _

Prescription Use (Per 21 CFR 801.109) OR

Over-The-Counter Use

(Optional Format 1-2-96)

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.