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The DYNEX SmartPLEX MMRV IgG Assay Kit is a multiplex immunoassay intended for the qualitative detection of IgG antibodies to Measles, Mumps, Rubella, and Varicella-Zoster Virus (VZV) in human serum. The DYNEX SmartPLEX MMRV IgG Assay Kit is intended for use with the DYNEX Multiplier Analyzer.

The DYNEX SmartPLEX MMRV IgG Assay Kit is intended to be used as an aid in the determination of serological status to Measles, Mumps, Rubella, and Varicella-Zoster Virus (VZV) in human serum from adults and pediatrics age above 1 year. This kit is not intended for screening blood or plasma donors.

The performance of this device has not been established for use in neonates, pediative patients below 1 year of age, and immunocompromised patients, or for use at point of care facilities.

The DYNEX SmartPLEX MMRV IgG Assay Kit (SmartPLEX MMRV IgG Assay) uses multiplex immunoassay, a methodology that greatly resembles traditional ELISA, while permits simultaneous detection and identification of different antibodies in a single well. The reaction is processed in a 96 well microtiter plate, with six polystyrene beads embedded in each well of the plate. Four (4) different beads are coated with antigens for the detection of IgG antibodies to Measles, Mumps, Rubella and Varicella-Zoster virus in human serum. Two additional beads are included in each reaction well as filler beads. Specimen processing is fully automated on the Multiplier Analyzer.

The Multiplier Analyzer adds the patient serum specimen and reagents to each well of the 96well plate, after which the mixture is incubated at 37°C with shaking. After a wash cycle, unbound antibodies from the patient's specimen are removed. Anti-human polyclonal IgG antibody conjugated to horseradish peroxidase (HRP) is added after which the mixture is incubated at 37°C with shaking. A second wash step removes excess conjuqate, then luminol substrate is added to each well. The amount of antibody captured by the antigen is determined by the chemiluminescence triggered by the attached HRP. Raw data is captured as light photons which are converted into relative light intensity units (RLU).

The Multiplier software analyzes the image and generates a report that details the mean RLU signal for each target bead (MMRV) by test sample. In every assay a calibrator is run. The DYNEX SmartPLEX MMRV IgG Assay Kit is qualitative and produces a result defined as negative (NEG), equivocal (EQV) or positive (POS) for each target analyte. The result is calculated in the Multiplier software by dividing the test sample RLU values by the mean calibrator RLU value to produce an index value for each target.

Here's an analysis of the acceptance criteria and study data for the DYNEX SmartPLEX MMRV IgG Assay Kit, as requested, based on the provided FDA 510(k) summary.

Device Name: DYNEX SmartPLEX MMRV IgG Assay Kit

Indications for Use: Qualitative detection of IgG antibodies to Measles, Mumps, Rubella, and Varicella-Zoster Virus (VZV) in human serum, as an aid in the determination of serological status. Intended for use with the DYNEX Multiplier Analyzer, in adults and pediatrics age above 1 year. Not intended for screening blood or plasma donors, neonates, pediatric patients below 1 year, or immunocompromised patients, or for point-of-care facilities.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria values (e.g., "PPA must be >X%"). Instead, it presents the performance results obtained from the study and implies that these results were deemed acceptable for clearance. For this table, I will use the reported Clinical Performance (Method Comparison) as the primary indicator of device performance, specifically the Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) values.

Note: The acceptance criteria are "implied" as the document presents the results to demonstrate performance rather than explicitly stating pre-defined thresholds the device needed to meet for clearance.

2. Sample Sizes and Data Provenance

• Test Set Sample Size:
  • Clinical Performance (Method Comparison): N = 2512 retrospective human serum specimens.
    • Adults: N = 1676
    • Pregnant Women: N = 500
    • Pediatrics (age above 1 year): N = 336
  • Reproducibility and Within-Laboratory Precision: 22 serum samples, each tested 240 replicates.
  • Potential Cross-Reactivity: Variable N for each substance (e.g., ANA n=5, CMV n=6-8, EBV n=6-11).
• Data Provenance: Retrospective human serum specimens obtained from commercial vendors. The method comparison testing was performed at two US laboratory testing sites.

3. Number of Experts and Qualifications for Ground Truth

• The ground truth for clinical performance (method comparison) was established by FDA-cleared comparator tests, not through expert human readers or adjudicators for each individual case result. The agreement was measured against the results of these established assays.
• For specimens with equivocal results on the test device and comparator device, they were retested with two additional FDA-cleared methods.

4. Adjudication Method for the Test Set

• For equivocal results that remained equivocal after initial retesting with the comparator device, a "2/3 rule" was used to establish a consensus final comparator result. This means that if at least two out of the three comparator devices provided the same categorical result (Positive, Equivocal, or Negative), that result was taken as the consensus.
• Any remaining equivocal results (where no 2/3 consensus was reached or the consensus was still equivocal) were "counted against the clinical performance" of the SmartPLEX MMRV IgG Assay (this is implied by the 3x3 analysis where equivocal results from the test device are presented in comparison to the "Final Comparator Result").

5. MRMC Comparative Effectiveness Study

• No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This document describes the performance of an in vitro diagnostic (IVD) assay kit, which directly measures antibodies in serum. These types of devices do not typically involve human readers interpreting images or data to the extent that an MRMC study would be applicable. The performance is assessed by comparison to established laboratory methods or ground truth.

6. Standalone Performance

• Yes, standalone performance was done. The entire study is a standalone performance evaluation of the DYNEX SmartPLEX MMRV IgG Assay Kit in relation to comparator methods. The device's output (qualitative detection of IgG antibodies) is directly compared to the output of other FDA-cleared IVD assays. There is no "human-in-the-loop" component for this type of diagnostic assay, as its output is a direct measurement.

7. Type of Ground Truth Used

• The ground truth for the clinical performance study was primarily based on the results from one or more FDA-cleared comparator immunoassay devices. For ambiguous cases (equivocal results), a consensus derived from multiple FDA-cleared comparator methods using a "2/3 rule" was employed. This is a common method for establishing reference values in IVD studies where a perfect "gold standard" may not exist for all samples, or where the goal is to show substantial equivalence to established methods.

8. Sample Size for the Training Set

• The document does not specify a separate "training set" sample size or details about a training phase. For IVD assay kits, the development and optimization process (analogous to training) typically involves internal experimentation, formulation adjustments, and preliminary testing, rather than a distinct "training set" of patient samples in the same way an AI/ML algorithm would use labeled data. The provided data represents the validation/test set used for regulatory submission.

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

• Since a distinct "training set" as understood in AI/ML was not explicitly used or described in the context of this IVD assay kit, the concept of establishing ground truth for a training set is not directly applicable here. The focus is on the performance of the final, developed kit. The development process would have involved establishing specifications and ensuring the assay's ability to accurately detect the target antibodies, perhaps using characterized positive/negative panels, but this is not typically detailed as "ground truth for training" in 510(k) summaries for such devices.

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