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The BioPlex™ 2200 HSV-1 & HSV-2 IgG kit is a multiplex flow immunoassay intended for the qualitative detection and differentiation of IgG antibodies to herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) in human serum and EDTA or heparinized plasma. The test is indicated for sexually active individuals and expectant mothers as an aid for the presumptive diagnosis of HSV-1 or HSV-2 infection. The predictive value of positive or negative results depends on the population's prevalence and the pretest likelihood of HSV-1 and HSV-2.

The test is not FDA cleared for screening blood or plasma donors. The performance of this assay has not been established for use in a pediatric population, neonates and immunocompromised patients or for use at point of care facilities.

The BioPlex 2200 HSV-1 & HSV-2 IgG kit is intended for use with the Bio-Rad BioPlex 2200 System.

The BioPlex 2200 HSV-1 & HSV-2 IgG kit uses multiplex flow immunoassay, a methodology that greatly resembles traditional EIA, but permits simultaneous detection and identification of many antibodies in a single tube.

Two different populations of dyed beads are each coated with antigens associated with herpes simplex virus, types 1 and 2. The BioPlex 2200 System combines an aliquot of patient sample, sample diluent, and bead set reagent into a reaction vessel. The mixture is incubated at 37°C. After a wash cycle, anti-human IgG antibody, conjugated to phycoerythrin (PE), is added to the dyed beads and this mixture is incubated at 37°C. The excess conjugate is removed in another wash cycle, and the beads are re-suspended in wash buffer. The bead mixture then passes through the detector. The identity of the dyed beads is determined by the fluorescence of the dyes, and the amount of antibody captured by the antigen is determined by the fluorescence of the attached PE. Raw data is calculated in relative fluorescence intensity (RFI).

Three additional dyed beads, an Internal Standard Bead (ISB), a Serum Verification Bead (SVB) and a Reagent Blank Bead (RBB) are present in each reaction mixture to verify detector response, the addition of serum to the reaction vessel and the absence of significant non-specific binding in serum. Refer to the BioPlex 2200 System Operation Manual for more information.

The instrument is calibrated using a set of 4 distinct calibrator vials, supplied separately by Bio-Rad Laboratories.

Here's a breakdown of the acceptance criteria and the study details for the BioPlex 2200 HSV-1 and HSV-2 IgG kit, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document doesn't explicitly state "acceptance criteria" as a pass/fail threshold, but rather presents performance metrics. Thus, I've interpreted the "acceptance criteria" as the performance levels demonstrated by the predicate device (implicitly accepted by the FDA) and the "reported device performance" as the BioPlex 2200's performance as measured against a commercially available immunoblot.

Assumed "Acceptance Criteria" (based on predicate performance and FDA clearance of similar devices): High sensitivity and specificity, typically above 90% in relevant populations, to reliably detect and differentiate HSV-1 and HSV-2 IgG antibodies. Precision and reproducibility should also be high (low CV).

2. Sample Sizes Used for the Test Set and Data Provenance

• Sexually Active Individuals with HSV-1 test ordered: N = 289
• Sexually Active Individuals with HSV-2 test ordered: N = 286
• Expectant Mothers: N = 399
• CDC Panel: N = 100
• Low Prevalence Population (16-19 years, non-STD setting): N = 200

Data Provenance:

• Country of Origin: The comparative studies were "conducted at a total of 3 U.S. clinical sites." The low-prevalence study was conducted at "2 U.S. clinical testing sites." The CDC panel is from the U.S. Centers for Disease Control.
• Retrospective or Prospective: The comparative study in intended use populations (sexually active individuals and expectant mothers) was described as a "prospective study." The low-prevalence study used "remnant serum samples," which suggests a retrospective collection, but the study itself was presumably designed prospectively for analysis. The CDC panel samples are well-characterized.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

The document does not explicitly state the number of experts or their qualifications. The ground truth for comparative testing was established by a "commercially available immunoblot test" and a "masked, well characterized HSV serum panel from the CDC." This implies that the ground truth was based on the consensus or established characterization of these reference methods, rather than real-time expert adjudication of individual cases.

4. Adjudication Method for the Test Set

The document describes how equivocal results were handled for the comparative effectiveness study:

• "For purposes of sensitivity calculations, the BioPlex 2200 equivocal results were assigned to the opposite clinical interpretation than that of the corresponding immunoblot result."
• "Likewise, immunoblot equivocal results were assigned to the opposite clinical interpretation than that of the BioPlex 2200 result."

This method effectively forces equivocal results into either positive or negative, but it's important to note that this is a specific approach for calculating sensitivity and specificity and not a general adjudication method for reporting results. It doesn't describe an expert panel adjudication.

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, a multi-reader multi-case (MRMC) comparative effectiveness study was not conducted. This device is an in-vitro diagnostic (IVD) assay that directly measures antibodies; it does not involve human readers interpreting images, and therefore, does not involve AI assistance for human readers.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done

Yes, the studies presented are standalone (algorithm only) performance analyses. The BioPlex 2200 HSV-1 and HSV-2 IgG kit is an automated system that processes samples and provides quantitative (Relative Fluorescence Intensity, RFI) or qualitative (Positive, Equivocal, Negative) results without direct human interpretive input beyond running the instrument and reviewing the automated output. Its performance is compared directly against the immunological ground truth.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

The ground truth used for the comparative studies was:

• A commercially available immunoblot test (e.g., Focus HerpesSelect 1 and 2 Immunoblot IgG).
• A masked, well-characterized HSV serum panel from the CDC. These panels are typically established through extensive testing using multiple reference methods and expert consensus on their true status.

8. The Sample Size for the Training Set

The document describes studies for performance validation of the device. It does not provide information on a "training set" for the development of the BioPlex 2200 assay itself. IVD devices like this are typically developed internally by the manufacturer using their own validation processes, and the 510(k) submission focuses on clinical validation results rather than details of internal algorithm training. Therefore, the sample size for a training set (if applicable to the assay's internal development) is not disclosed in this summary.

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

Since information on a specific "training set" and its size is not provided (as it's beyond the scope of a 510(k) performance summary for an IVD), details on how its ground truth was established are also not available in this document.

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