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The ARCHITECT HAVAB-G assay is a chemiluminescent microparticle immunoassay (CMIA) for the qualitative detection of IgG antibody to hepatitis A virus (IgG anti-HAV) in human adult and pediatric serum from patients with signs and symptoms or at risk for hepatitis. The ARCHITECT HAVAB-G assay is used to determine the immune status of individuals to hepatitis A virus infection.

Warning: This assay has not been FDA cleared or approved for the screening of blood or plasma donors. This assay cannot be used for the diagnosis of acute HAV infection.

Assay performance characteristics have not been established when the ARCHITECT HAVAB-G assay is used in conjunction with other hepatitis assays.

The ARCHITECT HAVAB-G assay determines the presence of IgG anti-HAV in human serum. After an acute HAV infection, IgG anti-HAV levels rise quickly and may persist for life. The presence of IgG anti-HAV implies past HAV infection (recent or distant) or vaccination against HAV. Detectable levels above the assay cut-off suggest immunity to HAV infection. The ARCHITECT HAVAB-G assay is a two-step immunoassay for the qualitative detection of IgG anti-HAV in human serum using CMIA technology with flexible assay protocols, referred to as Chemiflex. In the first step, sample, assay diluent, and hepatitis A virus (human) coated paramagnetic microparticles are combined. IgG anti-HAV present in the sample binds to the hepatitis A virus (human) coated microparticles. After washing, the anti-human IgG acridinium-labeled conjugate that is added in the second step binds to IgG anti-HAV. Following another wash cycle, pre-trigger and trigger solutions are added to the reaction mixture. The resulting chemiluminescent reaction is measured as relative light units (RLUs). The presence or absence of IgG anti-HAV in the sample is determined by comparing the chemiluminescent signal in the reaction to the cutoff signal determined from an ARCHITECT HAVAB-G calibration. Specimens with signal to cutoff (S/CO) values > 1.00 are considered reactive for IgG anti-HAV. Specimens with S/CO values

The provided document describes the ARCHITECT HAVAB-G assay, a device for qualitative detection of IgG antibody to hepatitis A virus (IgG anti-HAV). The study demonstrates its performance relative to existing assays, ARCHITECT HAVAB-M and AxSYM HAVAB 2.0, to establish substantial equivalence.

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" in a numerical or percentage format. Instead, the performance is presented as Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) compared to a "HAV IgG Final Status as determined by ARCHITECT HAVAB-M and AxSYM HAVAB 2.0 assays." The implicit acceptance criterion is that these agreement rates should be sufficiently high to demonstrate substantial equivalence to the predicate devices.

The broad 95% confidence intervals for small sample sizes (e.g., Vaccine Recipients NPA, Prospective pediatric population PPA) indicate less certainty for those specific subgroups, but the overall high agreement percentages across several populations likely met the internal criteria for substantial equivalence.

2. Sample size used for the test set and the data provenance:

• Sample Size: A total of 1147 specimens were used for the clinical performance evaluation.
• Data Provenance: Specimens were obtained from collection centers and vendors in the United States. The study appears to be retrospective for most populations (e.g., "Surplus pediatric population") and potentially prospective for specific groups ("Prospective pediatric population"). The overall nature is a collection of previously acquired samples and some prospectively collected ones.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

The document does not specify the number of experts or their qualifications for establishing the ground truth. It states that the ground truth ("HAV IgG Final Status") was "determined by ARCHITECT HAVAB-M and AxSYM HAVAB 2.0 assays." These are established diagnostic assays, implying that their results are considered the reference standard, not a subjective interpretation by human experts.

4. Adjudication method for the test set:

Not applicable. The ground truth was established by the results of two predicate assays, ARCHITECT HAVAB-M and AxSYM HAVAB 2.0, not through human adjudication of differing interpretations.

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 done. This device is an automated immunoassay for detecting antibodies, not an AI or imaging-based device requiring human reader interpretation or assistance.

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

Yes, the study presents the performance of the ARCHITECT HAVAB-G assay as a standalone algorithm (the CMIA technology is an automated process). The assay determines the presence or absence of IgG anti-HAV by comparing the chemiluminescent signal to a cutoff. There is no human interpretation or interaction required for the performance results tabulated.

7. The type of ground truth used:

The ground truth was established by the results of two reference diagnostic assays: ARCHITECT HAVAB-M and AxSYM HAVAB 2.0 assays. This is a form of comparative assay reference, where the device under evaluation is compared against an accepted method for determining the presence or absence of the target analyte.

8. The sample size for the training set:

The document does not specify a separate "training set" sample size. The studies listed (e.g., Assay Cut-Off Determination, Within-Laboratory Precision) describe analytical performance evaluations that would contribute to the assay's development and optimization, rather than a distinct 'training set' in the context of machine learning. For an immunoassay, the "training" involves setting assay parameters and cutoffs, which is typically done using various panels of known positive and negative samples, but these are not explicitly quantified as a "training set" in this type of submission.

9. How the ground truth for the training set was established:

Not explicitly detailed as a separate "training set" with ground truth in the document. For immunoassays, the ground truth for establishing parameters like the assay cutoff would typically involve using panels of well-characterized clinical samples (e.g., confirmed positive for HAV IgG, confirmed negative for HAV IgG) to establish appropriate thresholds for distinguishing positive from negative results. The "Assay Cut-Off Determination" study listed would be the primary mechanism for this.

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