(44 days)
This is an indirect immunoenzyme antibody test for the semi-quantitative detection of antinuclear antibodies in human serum, with specific identification of autoantibodies to the SS-A/Ro antigen. This test system is to be used as an aid in the detection of antibodies associated with systemic rheumatic disease. The results from this assay can be used as an aid in the diagnosis of autoimmune diseases.
This is an indirect immunoenzyme antibody test for the semi-quantitative detection of antinuclear antibody in human serum. The transfected HEP-2 cell line allows for the identification of anti-SS-A/Ro antibodies because of the unique staining pattern that these antibodies show on this cell line.
The provided text describes a 510(k) submission for the HEp-2000® Colorzyme® ANA-Ro Test System, which is an indirect immunoenzyme antibody test. The document focuses on demonstrating substantial equivalence to a predicate device (RELISA® SS-A/SS-B Antibody Test System, K955603) rather than defining explicit acceptance criteria with numerical thresholds. However, we can infer some criteria from the performance descriptions.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Inferred) | Reported (Device) Performance |
|---|---|
| For Normal Samples: Minimal false positives and consistency with non-transfected HEp-2 cells in negative results. | Out of 500 normal samples, 36 (7.2%) were positive on both the device and non-transfected HEp-2 cells at 1:40 dilution. 34 out of 36 positive samples showed identical staining patterns. The 2 discrepant samples were confirmed to have anti-SS-A/Ro antibodies. Samples negative on ANA tests were also negative in ELISA. |
| For Samples with only Ro/SS-A Antibodies: High detection rate and distinctive staining pattern for Ro/SS-A. | Out of 46 samples with confirmed anti-SS-A/Ro antibodies: 100% were positive with the device (distinctive Ro/SS-A staining pattern). 78% were positive with non-transfected HEp-2 cells (speckled pattern). |
| For Samples with Other Autoantibodies (without Ro/SS-A): Consistency in staining patterns with non-transfected HEp-2 cells. | Out of 230 samples with various autoantibodies: 333 staining patterns were identical on both substrates. 29 samples showed distinctive "SS-A/Ro" on the device. 23 of these 29 showed speckled on non-transfected HEp-2. The 6 "discrepant" samples (positive on device, negative on non-transfected HEp-2) all had SS-A/Ro antibodies confirmed by ELISA and Western blot. |
| Titer Comparisons for Ro/SS-A Antibodies: Higher titer values compared to non-transfected HEp-2 cells. | Samples containing anti-Ro/SS-A antibodies show higher titer values on the device than on non-transfected HEp-2 cells due to overexpression. |
| Titer Comparisons for Other Autoantibodies: No significant titer differences compared to non-transfected HEp-2 cells. | Sera with other autoantibody specificities do not show significant titer differences between the device and non-transfected HEp-2 cells. |
| Reproducibility: Consistent qualitative results and minimal quantitative variation across lots and runs. | For 10 characterized samples run on 3 different lots on 3 occasions: No negative sample showed positive results. All titer values were within one two-fold dilution of the established mean titer value. |
| Confirmation of SS-A/Ro Antibodies (Clinical Utility): Distinctive SS-A/Ro pattern should correlate strongly with confirmed SS-A/Ro antibodies. | In a selected population of 349 ANA-positive samples, 239 showed the distinctive SS-A/Ro staining pattern with the device. 238 (99.6%) of these had positive ELISA tests for SS-A/Ro. 79 additional samples with strong speckled/homogeneous patterns also gave positive SS-A/Ro ELISA. Conclusion: Distinctive pattern is confirmatory, but its absence doesn't rule out SS-A/Ro. |
2. Sample Sizes and Data Provenance
- Normal Samples: 500 healthy blood donors (242 females, 258 males). Provenance: Not explicitly stated, likely clinical lab setting. Retrospective or Prospective: Not explicitly stated, but "were tested in parallel" suggests a batch analysis, which could be either.
- Sera from Patients with Only Ro/SS-A Antibodies: 46 patients with SLE or Sjögren's Syndrome. Provenance: Not explicitly stated, likely clinical lab setting. Retrospective or Prospective: Not explicitly stated.
- Sera from Patients with Autoantibodies other than SS-A/Ro: 230 patients with a variety of rheumatic and non-rheumatic diseases. Provenance: Not explicitly stated, likely clinical lab setting. Retrospective or Prospective: Not explicitly stated.
- Reproducibility Titer: 10 samples (CDC controls and characterized in-house sera). Provenance: CDC controls and in-house laboratory. Retrospective or Prospective: Not explicitly stated, likely retrospective for established controls.
- Confirmation SS-A/Ro Antibodies: 349 patients with known positive ANA tests (from a large rheumatology reference laboratory). Provenance: Clinical rheumatology reference laboratory. Retrospective or Prospective: Not explicitly stated, but "known positive ANA tests" suggests retrospective selection.
3. Number of Experts and Qualifications for Ground Truth
The document does not specify the "number of experts" used to establish ground truth in the context of interpretation of the device results (e.g., reading patterns). However, the ground truth for the presence of specific antibodies (SS-A/Ro) was established by ELISA testing and Western immunoblotting, which are established laboratory methodologies. The interpretation of these confirmatory tests would be performed by trained laboratory personnel, but no specific number or qualifications of "experts" are provided beyond implied laboratory competence.
4. Adjudication Method for the Test Set
No explicit adjudication method (e.g., 2+1, 3+1) for the test set results interpreted by the device is mentioned. The assessment often involved comparing the device's staining patterns to those on non-transfected HEp-2 cells, with discrepancies resolved by ELISA and Western immunoblotting (which serve as the ultimate ground truth).
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study involving human readers with and without AI assistance was reported. This device is an in vitro diagnostic test system that produces a staining pattern for visual interpretation, not an AI model providing automated interpretations or assistance. The comparison is between two different laboratory substrates.
6. Standalone (Algorithm Only) Performance Study
This is an in vitro diagnostic test kit that produces a visual result (staining pattern) to be interpreted by a human. It does not employ an AI algorithm in the standalone sense. The results are visual patterns on cells.
7. Type of Ground Truth Used
The ground truth used was primarily a combination of:
- Confirmatory Laboratory Tests: ELISA testing and Western immunoblotting for the presence of specific autoantibodies (e.g., anti-SS-A/Ro).
- Clinical Diagnoses: Patients were selected based on diagnoses like SLE or Sjögren's Syndrome, and "known history of rheumatic diseases" for normal samples.
- Established Reference Materials: CDC controls and well-characterized in-house sera were used for reproducibility.
8. Sample Size for the Training Set
The document describes studies for validating the device's performance, but it does not mention a "training set" in the context of an AI/machine learning model. The HEp-2000® cell line itself is "transfected" to overexpress the SS-A/Ro antigen, but this is a biological modification, not an algorithmic training process with a data set.
9. How Ground Truth for the Training Set Was Established
As there is no "training set" for an AI algorithm, this question is not applicable to the described device. The "ground truth" equivalent for the development of the HEp-2000® cell line would be the biological understanding of how the transfected cells respond to SS-A/Ro antibodies compared to non-transfected cells, which is based on established scientific principles in immunology and cell biology.
§ 866.5100 Antinuclear antibody immunological test system.
(a)
Identification. An antinuclear antibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoimmune antibodies in serum, other body fluids, and tissues that react with cellular nuclear constituents (molecules present in the nucleus of a cell, such as ribonucleic acid, deoxyribonucleic acid, or nuclear proteins). The measurements aid in the diagnosis of systemic lupus erythematosus (a multisystem autoimmune disease in which antibodies attack the victim's own tissues), hepatitis (a liver disease), rheumatoid arthritis, Sjögren's syndrome (arthritis with inflammation of the eye, eyelid, and salivary glands), and systemic sclerosis (chronic hardening and shrinking of many body tissues).(b)
Classification. Class II (performance standards).