(222 days)
The IMMULITE® 2000 Syphilis Screen test is a treponemal testing procedure for the qualitative detection of antibodies to Treponema pallidum in human serum or heparinized plasma on the IMMULITE 2000 analyzer as an aid in the diagnosis of syphilis.
The IMMULITE 2000 Syphilis Screen is not intended for use in screening blood or plasma donors.
The IMMULITE 2000 Syphilis Screen is a solid-phase, one-step chemiluminescent immunoassay. The solid phase (bead) is coated with biotinylated recombinant Treponema pallidum p17 (Tp17) antigen. The liquid phase consists of alkaline phosphatase (bovine calf intestine) conjugated to purified recombinant Treponema pallidum p17 (Tp17) antigen.
The patient sample and reagent are incubated together with the coated bead for 30 minutes. During this time, total antibody to Treponema pallidum in the sample forms an antigen sandwich complex with biotinylated recombinant Treponema pallidum pl 7 (Tp17) antigen on the bead and enzyme conjugated purified recombinant Treponema pallidum p17 (Tp17) antigen in the reagent. Unbound patient sample and enzyme conjugate are then removed by centrifugal washes. Finally, chemiluminescent substrate is added to the reaction tube containing the bead and the signal is generated in proportion to the bound enzyme.
Here's a breakdown of the acceptance criteria and study information for the IMMULITE® 2000 Syphilis Screen device, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state "acceptance criteria" as a separate section with predefined thresholds. Instead, it presents a method comparison study between the IMMULITE® 2000 Syphilis Screen and the predicate device (DiaSorin LIASION® Treponema Assay). The performance of the new device is demonstrated through its agreement with the predicate.
For the purpose of this request, the "acceptance criteria" are inferred from the good performance values observed in the method comparison study, particularly the high positive and negative agreement rates.
| Performance Metric | Acceptance Criteria (Implicit from Predicate Performance/Study Results) | Reported Device Performance (IMMULITE 2000 Syphilis Screen) |
|---|---|---|
| Method Comparison (Medically Diagnosed Syphilis Patients) | ||
| Positive Agreement (vs. LIAISON Treponema Assay) | High agreement (e.g., > 95%) | 99.3% (270/272) (95% CI: 97.4% - 99.9%) |
| Negative Agreement (vs. LIAISON Treponema Assay) | Sufficient agreement to demonstrate comparable performance (not explicitly stated a threshold, but >75% is shown here) | 75% (6/8) (95% CI: 34.9% - 96.8%) |
| Overall Agreement (vs. LIAISON Treponema Assay) | High overall agreement (e.g., > 95%) | 98.2% (276/281) (95% CI: 95.9% - 99.4%) |
| Method Comparison (Samples for Routine Syphilis Testing) | ||
| Positive Agreement (vs. LIAISON Treponema Assay) | High agreement (e.g., > 95%) | 99.4% (359/361) (95% CI: 98.0% - 99.9%) |
| Negative Agreement (vs. LIAISON Treponema Assay) | High agreement (e.g., > 95%) | 99.1% (558/563) (95% CI: 97.9% - 99.7%) |
| Overall Agreement (vs. LIAISON Treponema Assay) | High overall agreement (e.g., > 95%) | 99.2% (917/924) (95% CI: 98.4% - 99.7%) |
| Reproducibility (Between-site Coefficient of Variation - CV) | Comparable to predicate device (LIAISON Treponema Assay: 4.32% to 17.76%) | Lot 1: 7.1% to 22.6% |
| Lot 2: 6.1% to 29.7% (for the same 7 samples tested with both IMMULITE lots) |
2. Sample Sizes Used for the Test Set and Data Provenance:
- Medically Diagnosed Syphilis Patients: 281 samples
- Samples Sent for Routine Syphilis Testing: 924 samples
- Data Provenance: The document does not explicitly state the country of origin. It mentions "samples from various patient populations were tested," which suggests diverse sources, but no specifics are given. The study appears to be retrospective as it involves "samples from various patient populations were tested with both the IMMULITE Syphilis Screen and the LIAISON Treponema Assay," implying pre-collected samples.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
The document does not mention the use of experts to establish ground truth for the test set. The "ground truth" for comparison is the DiaSorin LIASION® Treponema Assay. For the "Medically Diagnosed Syphilis Patients" cohort, their diagnosis would likely have involved clinical assessments and other laboratory tests by healthcare professionals, but no specific number or qualifications of experts are provided for the study's ground truth determination.
4. Adjudication Method for the Test Set:
No adjudication method is described. The comparison is directly between the IMMULITE 2000 Syphilis Screen and the LIAISON Treponema Assay, which serves as the reference (ground truth for agreement calculations).
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done:
No, a multi-reader, multi-case (MRMC) comparative effectiveness study was not done. This device is an in vitro diagnostic (IVD) immunoassay, not an imaging or diagnostic device requiring human interpretation of results in the traditional sense of an MRMC study. Its performance is evaluated quantitatively or qualitatively against a reference method.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) Was Done:
Yes, a standalone performance evaluation of the IMMULITE® 2000 Syphilis Screen was performed. The device, an automated immunoassay, generates results without human intervention in the interpretation of the test itself. The study compared these standalone results directly against those of the predicate device (LIAISON Treponema Assay).
7. The Type of Ground Truth Used:
The primary "ground truth" for determining performance was the DiaSorin LIASION® Treponema Assay.
Additionally, for the "Medically Diagnosed Syphilis Patients" group, the "ground truth" was established by medical diagnosis, likely an aggregation of clinical findings and other laboratory results, preceding the testing with the LIAISON assay. The document states "Medically Diagnosed Syphilis Patients", implying an established patient status.
8. The Sample Size for the Training Set:
The document does not provide information on a training set sample size. As a diagnostic immunoassay, the development process typically involves internal optimization and validation, but specific "training set" and "test set" terminology in the context of machine learning algorithms (which this device is not) is not directly applicable or reported here. The clinical study described focuses on the device's performance against a predicate and existing patient cohorts.
9. How the Ground Truth for the Training Set Was Established:
Since a training set is not explicitly mentioned or relevant in the context of the reported study for this immunoassay device, the method for establishing its ground truth is not provided. Device development would involve rigorous analytical validation, but this is distinct from the type of ground truth establishment relevant to AI/ML model training.
§ 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).