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The ADVIA Centaur® Herpes-2 IgG (HSV2) assay is for in vitro diagnostic use in the qualitative determination of IgG antibodies to herpes simplex virus type 2 (HSV-2) in human serum and plasma (EDTA and lithium heparin) using the ADVIA Centaur systems. The test is indicated for testing sexually active adults or expectant mothers for aiding in the presumptive diagnosis of HSV infection. The predictive value of a positive or negative result depends on the prevalence of HSV-2 infection in the population and the pre-test likelihood of HSV-2 infection.

The test is not FDA cleared for screening blood or plasma donors. The performance of this assay has not been established for immunocompromised patients, pediatric patients or matrices other than human serum and plasma (EDTA and lithium heparin).

The ADVIA Centaur Herpes-2 IgG (HSV2) assay is a fully automated two-step sandwich immunoassay using indirect chemiluminometric technology. The specimen is incubated with the Solid Phase, which contains HSV-2-specific recombinant-gG2 antigen. Antigen-antibody complexes will form if anti-HSV-2 antibody is present in the specimen. The Lite Reagent contains monoclonal anti-human IgG labeled with acridinium ester, and is used to detect HSV-2 IgG in the specimen.

The provided document describes the performance of the ADVIA Centaur Herpes-2 IgG (HSV2) assay, which is an in vitro diagnostic device. The study aims to demonstrate that the device meets acceptance criteria for substantial equivalence to a predicate device.

Here's a breakdown of the requested information based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document presents performance characteristics and compares them against design requirements or expected outcomes.

2. Sample Size and Data Provenance

• Precision Study: 6 samples and Negative/Positive Controls. Each material tested in duplicate, twice a day for 20 days.
  • N = 80 replicates per level for within-lab precision.
• Sample Matrix Study: 68 sets of matched samples (serum, serum separator tube, EDTA plasma, lithium heparin plasma).
• Panel Testing:
  • ToRCH-mixed Zeptometrix panel: 24 characterized HSV samples.
  • CDC panel: 100 blind characterized HSV samples.
• Cross-Reactivity Study: 522 specimens across various clinical categories.
• Multi-site Reproducibility: 6 samples and Negative/Positive Controls.
  • N = 90 replicates per level (from 3 external sites, 5 days, 2 runs/day, 3 replicates/run).
• Clinical Study:
  • Total: 864 specimens (≥ 18 years of age), including 274 pregnant women.
  • Data Provenance: Specimens collected within the United States. The study was conducted at 3 independent external laboratories. The nature of the specimen collection implies it was prospective for the purpose of this study, although the individual samples may have been sourced retrospectively from biobanks or collected prospectively for the study itself. The document does not explicitly state "retrospective" or "prospective" for the clinical sample collection, but "collected within the United States" and tested at external labs suggests purpose-collected samples for the study.

3. Number of Experts and Qualifications for Ground Truth

• The document implies the use of "reference assay 1" for the ToRCH-mixed Zeptometrix panel and "results provided by the CDC" for the CDC panel, as well as a "Comparative Assay" and "validated Western Blot reference confirmatory test (University of Washington, Seattle)" for the clinical study and cross-reactivity assessment.
• Number of Experts: Not explicitly stated how many individual experts established the ground truth for these reference methods. The description refers to "characterized HSV samples" for panels and "validated Western Blot" from a university, which implies expert consensus or highly standardized laboratory procedures.
• Qualifications of Experts: Not explicitly stated (e.g., "radiologist with 10 years of experience" is not applicable here as it's an in vitro diagnostic test for antibodies). However, the use of "validated Western Blot" from a reputable institution (University of Washington, Seattle) and "CDC" as sources for ground truth implies the highest level of expertise and validated methodologies in serological testing.

4. Adjudication Method for the Test Set

• For the clinical study: Of the 864 specimens, 22 were equivocal with the Comparative Assay. These 22 samples were resolved by Western Blot testing. 20 were resolved to be negative, and 2 remained equivocal. This describes a form of adjudication where an equivocal result from one reference method is adjudicated by a more definitive reference method (Western Blot).
• No multi-reader consensus (e.g., 2+1, 3+1) is mentioned, as this is an in vitro diagnostic assay, not an image-reading task.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No MRMC comparative effectiveness study was done. This type of study is typically performed for AI/CAD systems that assist human readers in interpreting medical images, not for in vitro diagnostic assays like this one which provides a quantitative or qualitative result directly.

6. Standalone (Algorithm Only) Performance

• This device is an automated immunoassay (ADVIA Centaur HSV2 assay). Its performance is inherently "standalone" in the sense that it directly measures antibodies without human interpretation in the loop to generate the initial result. The reported sensitivity and specificity values are for the device (algorithm) itself against the established ground truth.

7. Type of Ground Truth Used

• Expert Consensus / Highly-validated Reference Methods:
  • For panels: "characterized HSV samples," "reference assay 1," and "results provided by the CDC."
  • For clinical and cross-reactivity studies: A Comparative Assay (likely another FDA-cleared or well-established commercial immunoassay) and a validated Western Blot reference confirmatory test (University of Washington, Seattle). Western Blot is generally considered a highly specific and confirmatory test for antibody presence in serology. The use of a confirmatory test like Western Blot for equivocal results strengthens the ground truth.

8. Sample Size for the Training Set

• The document describes a 510(k) submission for an in vitro diagnostic device (immunoassay). Immunoassays are based on biochemical reactions and established calibration curves, not typically on machine learning models requiring large "training sets" in the same sense as AI/ML software. Therefore, a "training set" for an algorithm, as understood in AI/ML, isn't applicable or mentioned for this device. The development process would involve characterization, optimization, and validation using various samples, but not "training data" for a learnable algorithm.

9. How the Ground Truth for the Training Set Was Established

• As explained in point 8, the concept of a "training set" with ground truth establishment in the AI/ML sense does not apply to this immunoassay. The device's performance is driven by its reagent chemistry and instrumentation, not by a trained algorithm.

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