(84 days)
The TECHLAB H. PYLORI CHEK™ test is an enzyme immunoassay for the qualitative detection of Helicobacter pylori specific antigen. It is intended for use with human fecal specimens to aid in the diagnosis of H. pylori infection and to demonstrate loss of H. pylori antigen following treatment. The test can be used with unpreserved fecal specimens and fecal specimens preserved in transport media from patients suspected of H. pylori infection. Testing of patients to demonstrate loss of H. pylori antigen following treatment should be performed no sooner than 4 weeks after completion of the treatment regimen. Test results should be taken into consician in conjunction with the patient history and symptoms.
The H. PYLORI CHEK™ test uses antibodies specific to H. pylori antigen. The Microassay Plate in the kit contains immobilized capture antibodies aqainst H. pylori antigen. The Conjugate consists of antibodies specific to H, pylori antigen conjucated to horseradish peroxidase. In the assay, an aliquot of a diluted fecal specimen is transferred to a microassay well containing the Conjugate. If the antigen is present in the specimen, it will bind to the Coniugate and to the immobilized capture antibody during the incubation phase. Any unbound material is removed during the washing steps. Following the addition of Substrate, a color is detected due to the enzyme-antibody-antigen complexes that formed in the presence of antigen.
Acceptance Criteria and Study for H. PYLORI CHEK™ Test
This document describes the acceptance criteria for the H. PYLORI CHEK™ test, an enzyme immunoassay for the qualitative detection of Helicobacter pylori specific antigen in human fecal specimens, and the studies performed to demonstrate that the device meets these criteria.
1. Table of Acceptance Criteria and Reported Device Performance
| Parameter | Acceptance Criteria (Implicit from Predicate/Clinical Need) | Reported Device Performance (H. PYLORI CHEK™) |
|---|---|---|
| Initial Diagnosis | ||
| Sensitivity | High sensitivity to detect H. pylori infections. | 100% (95% CI: 89.3% - 98.9%) against Composite Reference Method (CRM) |
| Specificity | High specificity to avoid false positives. | 96.1% (95% CI: 89.2% - 98.7%) against CRM |
| Post-Therapy | ||
| Sensitivity | Acceptable sensitivity to demonstrate loss of antigen | 77.8% (95% CI: 45.3% - 93.7%) against CRM |
| Retrospective Sample Study | ||
| Percent Positive Agreement | 100% agreement with FDA cleared commercial ELISA | 100% (95% CI: 95.1% - 100.0%) |
| Percent Negative Agreement | 100% agreement with FDA cleared commercial ELISA | 100% (95% CI: 96.9% - 100.0%) |
| Reproducibility | Consistent results across sites, operators, and lots. | 97.5% correlation among different locations, multiple technicians, and two kit lots over a 5-day period. |
| Analytical Specificity (Cross-Reactivity) | No interference from common intestinal organisms and viruses. | None of the tested common intestinal organisms or viruses interfered with device performance. |
| Inclusivity | Reactivity with described H. pylori populations. | All tested H. pylori strains (including ATCC 700392, ATCC 43526, ATCC 43504, JP26) generated a positive result. |
| Interfering Substances | No effect on results from specified interfering substances. | No effect on positive or negative results from a comprehensive list of substances (e.g., medications, food components). |
| Analytical Sensitivity (LoD) | Low limit of detection for H. pylori antigen. | 6.70 ng/mL in fecal matrix (0.13 ng/test); 26.57 ng/mL in Cary-Blair media; 18.19 ng/mL in C&S media. |
| Precision (Intra-Assay & Inter-Assay) | Consistent results within and between assays. | Positive specimens tested as expected; negative specimens consistently tested negative (intra-assay). Positive samples tested as expected 98.3%, negatives 97.8% (inter-assay). |
| Fresh vs. Frozen Samples | Antigen stability maintained in frozen samples. | No conversion of positive-to-negative or negative-to-positive results in samples stored frozen for up to 14 days. |
| Prozone Effect | No high-dose hook effect. | No overall prozone effect observed; elevated antigen levels did not affect detection. |
2. Sample Size and Data Provenance for Test Sets
- Initial Diagnosis: 109 patients. The data was collected prospectively from patients undergoing endoscopy as part of routine care at 6 independent sites. The country of origin is not explicitly stated but is implicitly within the US given the FDA submission.
- Post-Therapy: 9 samples from patients being tested post-therapy. Data provenance is similar to the initial diagnosis group (prospectively collected, unclear country of origin but likely US).
- Retrospective Sample Study: 196 samples (75 positive, 121 negative by comparison ELISA). The provenance is "retrospective," and the country of origin is not specified but commonly implies US labs for FDA submissions unless otherwise noted.
3. Number of Experts and Qualifications for Ground Truth in Test Set
The document does not explicitly state the number of experts or their specific qualifications (e.g., years of experience as a radiologist) for establishing the ground truth.
For the Initial Diagnosis and Post-Therapy studies, the ground truth was established by a Composite Reference Method (CRM). This CRM consisted of:
* Rapid urease testing of biopsy samples.
* Histology of biopsy samples.
For the Retrospective Sample Study, the ground truth was an FDA cleared commercial ELISA.
4. Adjudication Method for the Test Set
The adjudication method for establishing the ground truth based on the Composite Reference Method (CRM) (rapid urease and histology) is not explicitly described. It is implied that a consensus or predefined rule was used to combine these two methods to determine the CRM positive or negative status. No adjudication by human readers for the device under evaluation is mentioned for this standalone performance study.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was mentioned or performed. This study focuses on the standalone performance of the diagnostic test.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
Yes, a standalone performance study was conducted. The performance data for the H. PYLORI CHEK™ test (e.g., sensitivity, specificity, agreement) are reported as the performance of the device without human interpretation (other than reading the device output). While visual reading of plates was also mentioned (achieving 99% agreement with spectrophotometric results), the primary reported performance metrics are based on the more objective dual wavelength spectrophotometric analysis.
7. Type of Ground Truth Used
The type of ground truth used was:
- Composite Reference Method (CRM): For the initial diagnosis and post-therapy studies, which combined rapid urease and histology from biopsy samples. This is considered a high-standard clinical ground truth.
- FDA cleared commercial ELISA: For the retrospective sample study, representing a comparative method ground truth.
8. Sample Size for the Training Set
The document does not provide information about a separate training set or its sample size. This type of device (enzyme immunoassay) typically does not involve a "training set" in the same way machine learning algorithms do. Instead, it relies on extensive analytical validation and clinical performance studies to establish its effectiveness.
9. How Ground Truth for the Training Set Was Established
As no explicit training set for an AI/ML algorithm is mentioned, there is no information provided on how ground truth for a training set would have been established. The development of this immunoassay would involve internal R&D and validation, but these stages are distinct from the "training set" concept in AI/ML.
§ 866.3110
Campylobacter fetus serological reagents.(a)
Identification. Campylobacter fetus serological reagents are devices that consist of antisera conjugated with a fluorescent dye used to identifyCampylobacter fetus from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by this bacterium and provides epidemiological information on these diseases.Campylobacter fetus is a frequent cause of abortion in sheep and cattle and is sometimes responsible for endocarditis (inflammation of certain membranes of the heart) and enteritis (inflammation of the intestines) in humans.(b)
Classification. Class I (general controls).