(342 days)
Syphilis Health Check is a qualitative rapid membrane immunochromatographic assay for the detection of Treponema pallidum (syphilis) antibodies in human whole blood, serum or plasma. This product can be used as an initial screening test or in conjunction with a non-treponemal laboratory test and clinical findings, may aid in the diagnosis of syphilis infection. This test is not intended for use in screening blood or plasma donors.
SYPHILIS HEALTH CHECK is a rapid qualitative screening test for detection of human antibodies to TP in serum, plasma or whole blood. The method employs an unique combination of anti-human immunoglobulins gold conjugate and highly purified TP recombinant proteins to specifically detect anti-TP antibodies. The test mainly detects IgG and IgM will also react in case of high concentrations. As the samples flow through the absorbent device, the anti-human immunoglobulins/protein A dye conjugate binds to the human immunoglobulins forming an antigen-antibody complex. This complex binds to the recombinant protein in the positive reaction zone and produces a pink-rose colored band. In the absence of anti TP antibodies, there is no line in the positive reaction zone. The reaction mixture continues flowing through the absorbent device past the reaction and control zones. Unbound conjugate binds to the reagents in the control zone producing a pink-rose color band, demonstrating that the reagents are functioning correctly.
Here's a breakdown of the acceptance criteria and the study details for the Syphilis Health Check device, based on the provided 510(k) summary:
Acceptance Criteria and Reported Device Performance
| Metric | Acceptance Criteria (Predicate Device K001552) | Reported Device Performance (Syphilis Health Check) |
|---|---|---|
| Sensitivity (Treponemal tests) | > 97% | > 98% (overall: 98.5%) |
| Specificity (Treponemal tests) | > 97% | > 98% (overall: 97.3%) |
| Positive Agreement (RPR total) | Not explicitly stated (predicate is EIA) | 95.6% (95% C.I. = 93.4 - 97.2%) |
| Negative Agreement (RPR total) | Not explicitly stated (predicate is EIA) | 90.5% (95% C.I. = 88.2 - 92.4%) |
| Overall Agreement (RPR total) | Not explicitly stated (predicate is EIA) | 92.4% (95% C.I. = 90.8 - 93.8%) |
| Positive Agreement (Treponemal total) | Not explicitly stated (predicate is EIA) | 98.5% (95% C.I. = 97.1 - 99.4%) |
| Negative Agreement (Treponemal total) | Not explicitly stated (predicate is EIA) | 97.3% (95% C.I. = 95.9 - 98.4%) |
| Overall Agreement (Treponemal total) | Not explicitly stated (predicate is EIA) | 97.8% (95% C.I. = 96.9 - 98.6%) |
Note: The predicate device uses Enzyme ImmunoAssay (EIA) with a stated sensitivity and specificity of >97%. The Syphilis Health Check is a rapid immunochromatographic membrane assay, so direct acceptance criteria for RPR comparisons are not explicitly stated for the predicate, but the overall performance values of the new device are provided for both RPR and treponemal comparisons.
Study Information
2. Sample size used for the test set and the data provenance:
- Total Test Sample Size: 1292 samples
- Prospective Samples: 880 patient samples
- Provenance: Collected from five clinical study sites (four STD clinics and one hospital clinic) in the U.S. Patients were suspected positive for syphilis and exhibiting symptoms.
- Retrospective Samples: 412 frozen samples
- Provenance: Purchased from outside commercial vendors and blood centers. These included 149 banked RPR and treponemal reactive serum samples, 28 serum samples from primary/secondary patients (treated but symptomatic), and 138 frozen serum/plasma samples.
- Clinically Diagnosed Samples: 164 well-characterized serum samples (from treated and untreated patients with primary, secondary, and latent syphilis infections).
- Provenance: Obtained from a clinic serving a population with various infectious diseases.
- Prospective Samples: 880 patient samples
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document does not specify the number of individual experts or their qualifications (e.g., radiologist with 10 years of experience) used to establish the ground truth for the test set.
- Ground truth was established by "reference methods" such as RPR (Non-Treponemal), TPPA, TPHA, FTA, ELISA, and MHA-TP. These are established laboratory tests, implying that the ground truth was determined by qualified laboratory personnel performing these assays, not necessarily by clinical experts adjudicating cases beyond the initial patient suspicion and clinical diagnosis for the clinically diagnosed samples.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- The document does not explicitly describe an adjudication method for conflicting results between reference methods or between the device and reference methods (e.g., 2+1, 3+1).
- For the "Suspected and Known Positive Syphilis Samples" retrospective study, it mentions that some samples with discrepancies between initial RPR/Treponemal results and Syphilis Health Check were "further tested by an outside laboratory for TPPA titer and Syphilis Health Check results." This implies a form of re-testing or confirmatory testing for discordant results but not a structured expert adjudication panel.
- For the "Clinically Diagnosed" samples, a panel of 164 samples was "well-characterized" and tested with RPR, TPPA, and FTA-ABS as reference assays, suggesting these reference methods collaboratively defined the "known clinical status."
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:
- No MRMC comparative effectiveness study was done. This device is a rapid diagnostic test (immunochromatographic assay) designed for standalone use, not a diagnostic imaging AI tool requiring human-in-the-loop performance measurement or evaluation of human reader improvement. The "readers" of this test are individuals visually interpreting a pink-rose colored band.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, a standalone performance study was done. The entire performance evaluation presents the Syphilis Health Check test's results in isolation, comparing its output directly to that of established reference methods (RPR, TPPA, TPHA, FTA, ELISA, MHA-TP). The visual interpretation of the test result (presence or absence of a colored band) is the direct output of the device, without human interpretive assistance beyond reading the test itself.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The ground truth was established by reference laboratory assays (established Treponemal and non-Treponemal tests). These include RPR, TPPA, TPHA, FTA, ELISA, and MHA-TP.
- For the "clinically diagnosed" samples, the ground truth was based on "well-characterized clinically diagnosed serum samples" using these reference assays to confirm clinical status (primary, secondary, or latent syphilis).
8. The sample size for the training set:
- The document does not specify a training set sample size. As an immunochromatographic rapid diagnostic test, it is a chemical/biological assay and not an AI algorithm that typically undergoes a distinct "training phase" with a labeled dataset in the same way machine learning models do. Its "development" would involve optimization of reagents, concentrations, and assay design rather than data-driven machine learning training.
9. How the ground truth for the training set was established:
- Since there's no explicit "training set" for an AI algorithm outlined, this question is not directly applicable. The performance characteristics of the device were evaluated against established reference methods, as described in point 7.
§ 866.3830
Treponema pallidum treponemal test reagents.(a)
Identification. Treponema pallidum treponemal test reagents are devices that consist of the antigens, antisera and all control reagents (standardized reagents with which test results are compared) which are derived from treponemal sources and that are used in the fluorescent treponemal antibody absorption test (FTA-ABS), theTreponema pallidum immobilization test (T.P.I.), and other treponemal tests used to identify antibodies toTreponema pallidum directly from infecting treponemal organisms in serum. The identification aids in the diagnosis of syphilis caused by bacteria belonging to the genusTreponema and provides epidemiological information on syphilis.(b)
Classification. Class II (performance standards).