Performance comparison of the Maxim and Sedia Limiting Antigen Avidity assays for incidence surveillance

BackgroundTwo manufacturers, Maxim Biomedical and Sedia Biosciences Corporation, supply US CDC-approved versions of the HIV-1 Limiting Antigen Avidity EIA (LAg assay) for detecting recent HIV infection in cross-sectional incidence estimation. This study assesses and compares the performance of the Maxim and Sedia LAg assays for incidence surveillance.\n\nMethodsWe ran both assays on a panel of 2,500 well-characterized HIV-1-infected specimens, most with estimated dates of (detectable) infection. We analysed concordance of assay results, assessed reproducibility using repeat testing and estimated the critical performance characteristics of a test for recent infection--mean duration of recent infection (MDRI) and false-recent rate (FRR)--for a range of normalized optical density (ODn) recency discrimination thresholds, alone and in combination with viral load thresholds. We further defined three hypothetical surveillance scenarios and evaluated overall performance for incidence surveillance, defined as the precision of incidence estimates, by estimating context-specific performance characteristics.\n\nResultsThe Maxim assay produced lower ODn values than the Sedia assay on average, largely as a result of higher calibrator readin...Continue Reading