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MRL Diagnostics' HSV-2 ELISA IgG test is intended for qualitatively detecting the presence or absence of human IgG class antibodies to HSV-2 in human sera. In conjunction with the MRL HSV-1 ELISA IgG, 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 population's prevalence and the pretest likelihood of HSV-2 infection. The performance of this assay has not been established for use in a pediatric population, for neonatal screening, for testing of immunocompromised patients, or for use with automated equipment.

In the MRL Diagnostics HSV-2 ELISA IgG assay, the polystyrene microwells are coated with recombinant gG-2 antigen. Diluted serum samples and controls are incubated in the wells to allow specific antibody present in the samples to react with the antigen. Nonspecific reactants are removed by washing, and peroxidase-conjugated anti-human IgG is added and reacts with specific IgG. Excess conjugate is removed by washing. Enzyme substrate and chromogen are added, and the color is allowed to develop. After adding the Stop Reagent, the resultant color change is quantified by a spectrophotometric reading of optical density (OD). Sample optical density readings are compared with reference cut-off OD readings to determine results.

Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text for the MRL Diagnostics HSV-2 ELISA IgG device (K993724):

The provided text describes a 510(k) summary for a medical device, which typically focuses on demonstrating substantial equivalence to a predicate device rather than setting explicit "acceptance criteria" for performance in the same way a clinical trial might. However, we can infer performance targets based on the data presented and comparisons to the reference methods.

1. Table of Acceptance Criteria (Inferred) and Reported Device Performance

2. Sample Sizes and Data Provenance

• Test Sets:

  • Sexually Active Adults: n = 246 (includes 5 atypical WBs, 1 ELISA equivocal removed from final calculations)
  • Expectant Mothers: n = 241 (includes 3 atypical WBs, 1 ELISA equivocal removed from final calculations)
  • Culture Positives: n = 63 (used for sensitivity relative to culture and WB)
  • Low Prevalence Population (College Students): n = 81 (includes 1 atypical WB removed from final calculations)
  • HSV-1 WB Positive/HSV-2 WB Negative Sera: n = 287 (collected from expectant mothers, sexually active adults, low prevalence persons, and HSV-1 culture positives. Excludes 1 equivocal ELISA result.)
  • CDC Panel: Panel size not explicitly stated, but described as "37% positive and 63% negative samples."
  • Cross-reactivity with Taxonomically Related Viruses: n = 27 (sera from HSV sero-negative by other manufacturers' FDA-cleared HSV ELISAs, and IFA IgG positive for CMV, EBV VCA, HHV6, VZV)

• Data Provenance:

  • The studies were performed by "an outside investigator" and "an internal investigator" (for reproducibility studies).
  • Sera for the main performance studies (sexually active adults, expectant mothers, low prevalence population, type specificity) were "sequentially submitted to the laboratory, archived, and masked." This suggests retrospective analysis of archived samples.
  • The reference Western Blot was from a "Pacific Northwest university."
  • CDC Panel: "from the CDC."
  • Cross-reactivity: Sera were either from HSV sero-negative patients by other cleared ELISAs or IFA IgG positive for specific viruses.

3. Number of Experts and Qualifications for Ground Truth

• Number of Experts: Not specified.
• Qualifications of Experts: The ground truth for the main performance studies was established using HSV-2 Western blot and HSV-2 Culture from a "Pacific Northwest university." While the expertise of the individuals performing and interpreting these reference methods is not explicitly detailed (e.g., "Medical Technologist with X years of experience," "Virologist," etc.), the use of a university lab and established methods implies qualified personnel. The CDC also provided a panel, suggesting expertise in their characterization.

4. Adjudication Method for the Test Set

• None explicitly stated. For the primary studies, the reference method (Western Blot or Culture) was considered the definitive ground truth, and the device's results were compared against it. Ambiguous results (e.g., "atypical Western blots," "ELISA equivocal") were generally excluded from the primary sensitivity/specificity calculations for clarity, rather than going through an adjudication process. For cross-reactivity studies, discrepant results between the MRL device and other FDA-cleared ELISAs were analyzed using a type-specific Western blot.

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

• No, a MRMC comparative effectiveness study was not done. This document describes the performance of an in vitro diagnostic device (an ELISA assay) that processes samples and provides quantitative/qualitative results, typically read by a lab technician. It does not involve human readers interpreting images or specific cases with and without AI assistance in the way a radiological device might. The "readers" here are the lab personnel performing the assay and interpreting the spectrophotometric readings against cut-off values.

6. Standalone Performance Study (Algorithm Only)

• Yes, this is a standalone performance study. The document reports the performance of the MRL Diagnostics HSV-2 ELISA IgG device (an algorithm/assay that processes samples and produces results) directly compared against established reference methods (Western Blot, Culture, CDC panel) without human interpretation as an intermediate step to establish disease status. The results reported are the direct output of the ELISA assay.

7. Type of Ground Truth Used

• Reference Methods:
  • Western Blot (WB): Primarily used for determining HSV-2 sero-status in most studies (sexually active adults, expectant mothers, low prevalence population, type specificity). This is a well-established laboratory reference method for antibody detection.
  • Culture: Used for identifying "culture positive patients" for sensitivity relative to infection. This is a direct method for detecting HSV virus.
  • CDC Panel results: Used as a reference for agreement for a masked, characterized serum panel. The specific ground truth method used by the CDC for this panel is not detailed but implies high confidence in their characterization.
  • Other FDA cleared HSV ELISAs and IFA IgG positivity: Used as initial screening for cross-reactivity studies, with discrepancies resolved by type-specific Western Blot.

8. Sample Size for the Training Set

• Not applicable / Not specified. ELISA assays are essentially "fixed" algorithms (chemical reactions, spectrophotometric measurement, and a pre-defined cut-off value). They are developed and optimized (a "training phase" in a general sense, but not in the machine learning/AI sense), but there isn't a "training set" in the context of an AI algorithm or a specific data set used to iteratively train a model. The assay's parameters (e.g., recombinant gG-2 antigen, reaction conditions, cut-off values) are established during development.

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

• Not applicable. As noted above, this isn't an AI/machine learning device that uses a "training set" with ground truth in the conventional sense. The "ground truth" for developing and validating the assay's components and cut-offs would have been derived from studies comparing various assay configurations against known positive and negative samples, likely characterized by reference methods like Western Blot or culture. However, the details of that developmental-phase ground truth establishment are not present in this 510(k) summary, which focuses on the final validation study of the developed device.

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