(133 days)
The Gold Standard Diagnostics Borrelia burgdorferi IgG/IgM ELISA Test Kit is intended as a qualitative test for the detection of IgG and IgM antibodies to Borrelia burgdorferi sensu stricto in human serum from symptomatic patients or people suspected of infection. When used as the first-tier screening test, positive and equivocal results must be confirmed through additional testing by one of the following methods:
• Standard two-tier test methodology (STTT) using an IgG and/or IgM blot testing following current interpretation guidelines, OR
• Modified two-tier test methodology (MTTT) using the Gold Standard Diagnostics Borrelia burgdorferi VlsE-OspC IgG/ IgM ELISA Test.
The assay can also be used as a second-tier confirmation test using the MTTT methodology when used with the Gold Standard Diagnostics Borrelia burgdorferi VlsE-OspC IgG/IgM ELISA Test as the first-tier screening test.
Positive test results by either the STTT or MTTT methodology are supportive evidence for the presence of antibodies and exposure to Borrelia burgdorferi, the cause of Lyme disease. A diagnosis of Lyme disease should be made based on the presence of Borrelia burgdorferi antibodies, history, symptoms, and other laboratory findings.
The kit includes 12 x 8 well Antigen Coated strips, Conjugate, Substrate, Stop Solution, Wash Buffer, Diluent, Negative Control, Positive Control, and Cutoff Control. The controls are provided to determine if the assay is functioning properly and to determine the antibody level. The reagents are sufficient for 96 determinations.
During the test procedure, antibodies to B. burgdorferi (sensu stricto) if present in the human serum sample will bind to the antigens coated onto the wells forming antigen-antibody complexes. Excess antibodies are removed by washing. A conjugate of goat anti-human IgG/IgM antibodies conjugated with horseradish peroxidase are then added, which binds to the antigen-antibody complexes. Excess conjugate is removed by washing. This is followed by the addition of a chromogenic substrate, tetramethylbenzidine (TMB). If specific antibodies to the antigen are present in the patients' serum, a blue color will develop. The enzymatic reaction is then stopped with a stopping solution causing the contents of the well to turn yellow. The wells are read photometrically with a microplate reader at 450nm.
The antigens used in the Gold Standard Diagnostics Borrelia burgdorferi IgG/IgM ELISA Test kit is a combination of B. burgdorferi sensu stricto strain B31 lysate, B. burgdorferi sensu stricto strain 2591 lysate, and a recombinant VlsE from B. burgdorferi sensu stricto strain B31. The lysates use spirochetes growing in BSK-H complete medium until mid-exponential phase. The recombinant VlsE protein is produced in E. coli SURE2 cells and purified by affinity chromatography. The purity of each antigen is assayed by SDS-PAGE followed by Coomassie staining and/or Western blotting.
The provided document describes the Gold Standard Diagnostics Borrelia burgdorferi IgG/IgM ELISA Test Kit and its performance in various studies. Here's a breakdown of the acceptance criteria and study details:
1. Table of Acceptance Criteria and Reported Device Performance (STTT comparison):
The document does not explicitly state pre-defined acceptance criteria for the comparative studies. Instead, it presents observed performance metrics (Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA)) against a predicate device. For the purpose of this response, I will highlight the reported performance metrics from the comparative study.
| Metric | Reported Device Performance (STTT) | Basis of Comparison |
|---|---|---|
| Positive Percent Agreement (PPA) | 96.0% (72/75) with 95% CI (88.8% - 99.2%) | Predicate IgG/IgM ELISA |
| Negative Percent Agreement (NPA) | 97.5% (434/445) with 95% CI (95.6% - 98.8%) | Predicate IgG/IgM ELISA |
1. Table of Acceptance Criteria and Reported Device Performance (MTTT Comparison):
Similar to the STTT comparison, the document reports observed performance metrics for the MTTT protocol against the STTT predicate.
| Metric | Reported Device Performance (MTTT) (Second-tier test of MTTT vs. STTT for first-tier positive/equivocal samples) | Reported Device Performance (MTTT) (MTTT vs. STTT for all prospective study samples) | Basis of Comparison |
|---|---|---|---|
| Positive Percent Agreement (PPA) | 100.0% (95% CI (90.3% - 100.0%)) | 100.0% (95% CI (90.3% - 100.0%)) | Predicate Immunoblots (STTT) |
| Negative Percent Agreement (NPA) | 27.8% (95% CI (9.7% - 53.5%)) | 97.1% (95% CI (95.1% - 98.4%)) | Predicate Immunoblots (STTT) |
2. Sample Size Used for the Test Set and Data Provenance:
For Comparison with Predicate Device (STTT):
- Sample Size: 520 serum samples.
- Data Provenance: Prospective samples submitted for Lyme serology testing. Collected from three sites (one internal and two external reference laboratories).
For MTTT Comparison (Prospective Study):
- Sample Size: 481 serum samples for the initial screening. Of these, 54 positive or equivocal samples were further tested.
- Data Provenance: Prospective samples submitted for Lyme serology testing. Collected from three sites (one internal and two external reference laboratories).
For Sensitivity Study (STTT and MTTT):
- Sample Size: 89 clinically characterized samples for STTT and 125 clinically characterized samples for MTTT.
- Data Provenance: Clinically characterized samples encompassing early, disseminated, and late stages of Lyme disease. The document doesn't specify geographical origin but implies a clinical context.
For CDC Panel (STTT and MTTT):
- Sample Size: 40 samples for STTT and 280 samples for MTTT.
- Data Provenance: Acquired from the Centers for Disease Control (CDC).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:
The document does not provide specific details on the number or qualifications of experts used to establish the ground truth for the test sets. The ground truth appears to be based on:
- "Clinically characterized samples" (for sensitivity studies).
- "Patients diagnosed with Lyme disease" and "healthy individuals" from the CDC panel.
- Comparison with predicate devices (for comparative studies).
4. Adjudication Method for the Test Set:
The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for resolving discrepancies or establishing ground truth within the test sets. For comparative studies, the predicate device results largely serve as the reference, and for sensitivity studies, samples are clinically characterized, implying pre-existing diagnoses.
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:
This device is an in-vitro diagnostic (IVD) ELISA test kit, not an AI-powered image analysis or diagnostic tool that involves human readers. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance is not applicable and was not performed.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done:
The device is an ELISA test kit designed to provide a qualitative result (positive, equivocal, negative) based on optical density readings. It functions as a standalone diagnostic assay without a human-in-the-loop component in its primary function. The interpretation of the results by laboratory personnel is part of standard lab practice, but the "standalone performance" in this context refers to the assay's accuracy in detecting antibodies. The reported PPA, NPA, and sensitivity studies reflect this standalone performance.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc):
The ground truth used for different studies varies:
- Comparison Studies with Predicate Device: The results of the legally marketed predicate devices (Trinity Biotech Captia™ Borrelia burgdorferi IgG/IgM ELISA Test Kit and Gold Standard Diagnostics Borrelia burgdorferi IgG/IgM Blot Tests) served as the reference standard.
- Sensitivity Studies: "Clinically characterized samples" and "patients diagnosed with Lyme disease" from the CDC panel. This implies a combination of clinical assessment, symptomology, and potentially other laboratory findings, which can be seen as a form of expert consensus or aggregated clinical data.
- Analytical Specificity and Cross-Reactivity: For analytical specificity, asymptomatic individuals from endemic and non-endemic regions were used. For cross-reactivity, samples confirmed positive for specific disease markers (from serum vendors) were used.
8. The Sample Size for the Training Set:
The document describes the determination of the assay cutoff but does not explicitly mention a "training set" in the context of machine learning or AI. For the cutoff determination:
- Assay Cutoff: 200 normal sera (100 from endemic, 100 from non-endemic regions).
- Verification: 125 characterized Lyme disease samples were used with the 200 normal samples for ROC analysis to verify the chosen cutoff.
9. How the Ground Truth for the Training Set Was Established:
As noted above, there isn't a "training set" in the typical AI sense. However, for the determination of the assay cutoff:
- Normal Sera: These were identified as "normal" based on their origin from non-diseased individuals in endemic and non-endemic regions.
- Characterized Lyme Disease Samples: These 125 samples were "characterized" for Lyme disease, implying a pre-established clinical diagnosis or a well-defined status as positive Lyme disease samples.
§ 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).