(138 days)
The ASCA-CHEK test is an enzyme-linked immunosorbent assay (ELISA) for the qualitative detection of human anti-S. cerevisiae antibodies (ASCA) in feces and serum. The test result is used as an aid in the diagnosis of Crohn's disease in combination with clinical and other laboratory findings. FOR IN VITRO DIAGNOSTIC USE.
The ASCA-CHEK test is an ELISA for the measurement of human anti-S. cerevisiae antibodies in feces and serum as an indicator of Crohn's disease in combination with other clinical and laboratory findings. The assay utilizes antigens of S. cerevisiae for capture and a polyvalent anti-human immunoglobulin conjugate. For feces, a specimen dilution of 1:10 and an OD 450 cut-off ≥0.150 or OD450620 ≥0.110 are used for the analysis. For serum, a specimen dilution of 1:1000 and an OD450 cut-off ≥0.110 or OD450620 ≥0.080 are used for the analysis. When human ASCA is present in fecal or serum specimens, the specific immunoglobulins bind to the S. cerevisiae antigens that are immobilized in the test well. Following this binding step, the polyvalent anti-human horseradish peroxidase (HRP) conjugate binds to the ASCA and reacts with the substrate to produce a positive result. The measurement of fecal and serum ASCA is an indicator of Crohn's disease within the setting of differentiating Crohn's disease from ulcerative colitis and IBS. This diagnostic method offers a simple to perform assay that may be used with either fecal or serum specimens.
Here's a breakdown of the ASCA-CHEK device's acceptance criteria and the study that supports it, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The provided document does not explicitly state pre-defined acceptance criteria (e.g., minimum sensitivity, specificity, or agreement percentages) that the device had to meet to be approved. Instead, it presents the performance data and then asserts that, based on these findings, the device is substantially equivalent. Therefore, the "acceptance criteria" inferred here are based on the reported "substantial equivalence" claim relative to the predicate devices.
| Metric (vs. Disease) | Target (Inferred from Predicate Performance or Substantial Equivalence Claim) | ASCA-CHEK Performance (All Patients + Controls) | ASCA-CHEK Performance (Adult Patients + Controls) | ASCA-CHEK Performance (Pediatric Patients + Controls) |
|---|---|---|---|---|
| Sensitivity | Similar to QUANTA Lite™ ASCA (64% in All; 75% in Adults; 58% in Peds) | 62% | 65% | 60% |
| Specificity | Similar to QUANTA Lite™ ASCA (95% in All; 96% in Adults; 95% in Peds) | 93% | 95% | 86% |
| Agreement (Overall) | Similar to QUANTA Lite™ ASCA (79% in All; 88% in Adults; 70% in Peds) | 78% | 84% | 68% |
| Metric (vs. QUANTA Lite™ ASCA) | Target (Inferred Acceptance Level for Equivalence) | ASCA-CHEK Performance (All Patients + Controls) | ASCA-CHEK Performance (Adult Patients + Controls) | ASCA-CHEK Performance (Pediatric Patients + Controls) |
| Positive Agreement | High (to show agreement with predicate) | 80%* | 78%* | 82%* |
| Negative Agreement | High (to show agreement with predicate) | 88%* | 94%* | 80%* |
| Overall Agreement | High (to show agreement with predicate) | 85%* | 89%* | 81%* |
*Note: The document references "Statistical Guidance on Reporting Results from Studies Evaluating Diagnostic" for these agreement percentages, suggesting these values were deemed acceptable for demonstrating equivalence.
2. Sample Size and Data Provenance
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Sample Sizes Used for the Test Set:
- All Patients plus Controls: N = 351 (for ASCA-CHEK vs Disease)
- Adult Patients plus Controls: N = 215 (for ASCA-CHEK vs Disease)
- Pediatric Patients plus Controls: N = 136 (for ASCA-CHEK vs Disease)
- Comparison to QUANTA Lite™ ASCA (overlapping groups): N = 274 (All), N = 138 (Adult), N = 136 (Pediatric)
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Data Provenance: The document does not explicitly state the country of origin or whether the data was retrospective or prospective. It refers to "Site: Pediatric Patients plus Controls" and "Site: Adult Patients plus Controls," implying data collection from specific clinical locations, but further details are not provided.
3. Number of Experts Used to Establish Ground Truth and Qualifications
The document does not specify the number of experts used or their qualifications for establishing the ground truth (diagnosis of Crohn's disease or control status). The "Disease" categorization likely stems from standard clinical diagnostic criteria and specialist evaluation, but the specifics are not detailed.
4. Adjudication Method
The document does not describe any adjudication method (e.g., 2+1, 3+1, none) for establishing the ground truth of the test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This device is an in-vitro diagnostic (ELISA), not an imaging or interpretation-based diagnostic that would typically involve multiple human readers. The study compares the performance of the new device (ASCA-CHEK) against the known disease state and against predicate ELISA devices.
6. Standalone Performance Study
Yes, a standalone performance study was done. The "ASCA-CHEK vs Disease" rows in the performance table represent the standalone performance of the algorithm (the ASCA-CHEK ELISA) in detecting true positive and true negative cases based on a clinical diagnosis of the disease or healthy control status.
7. Type of Ground Truth Used
The ground truth used is "Disease" status, which, in the context of diagnosing Crohn's disease, would typically be established by a combination of clinical findings, endoscopy, imaging, histology (pathology), and other laboratory tests. The document indicates the ASCA-CHEK test result is "an aid in the diagnosis of Crohn's disease in combination with clinical and other laboratory findings," implying that there's a reference standard (the "Disease" column) against which the device's output is compared. It is not explicitly stated if it was expert consensus, pathology alone, or outcomes data, but likely a clinical diagnosis based on established medical criteria.
8. Sample Size for the Training Set
The document does not provide information on the sample size for a training set. This is typical for a 510(k) submission where the primary focus is on demonstrating clinical performance and substantial equivalence of the finished device rather than detailing model development or training data. Being an ELISA, it might not have a "training set" in the sense of a machine learning algorithm.
9. How the Ground Truth for the Training Set Was Established
As no training set is described, this information is not provided in the document.
§ 866.5785 Anti-
Saccharomyces cerevisiae (S. cerevisiae ) antibody (ASCA) test systems.(a)
Identification. The Anti-Saccharomyces cerevisiae (S. cerevisiae ) antibody (ASCA) test system is an in vitro diagnostic device that consists of the reagents used to measure, by immunochemical techniques, antibodies toS. cerevisiae (baker's or brewer's yeast) in human serum or plasma. Detection ofS. cerevisiae antibodies may aid in the diagnosis of Crohn's disease.(b)
Classification. Class II (special controls). The special control is FDA's “Guidance for Industry and FDA Reviewers: Class II Special Control Guidance Document for Anti-Saccharomyces cerevisiae (S. cerevisiae ) Antibody (ASCA) Premarket Notifications.”