Data on the relationship of signal-to-cutoff ratio of two HIV antigen/antibody combination assays to subsequent confirmation of HIV-1 infection in a low-prevalence population

Abstract

HIV-1/2 antigen/antibody (Ag/Ab) immunoassays that detect HIV-1 and HIV-2 antibodies and HIV-1 p24 antigen are commonly used in the diagnosis of HIV-1/HIV-2 infections in human plasma/serum. Samples from patients with positive screening results require confirmation by antibody differentiation and/or HIV PCR assays. HIV screening assays are commonly reported as positive or negative based on a signal-to-cutoff (S/CO) threshold. For some HIV screening assays, the strength of the S/CO value correlates with likelihood that confirmatory testing will be positive. The data in this article provide results from two HIV Ag/Ab combination assays (Abbott Architect HIV Ag/Ab Combo Assay, a 4^th generation combination assay; Bio-Rad Bioplex 2200 HIV Ag-Ab Assay, a 5^th generation assay). The data include 23,331 HIV screening results, S/CO ratios, antibody differentiation or Western blot results (for samples with positive HIV screens), HIV-1 PCR results (if performed), patient location at time of testing, age, and sex. Distribution of S/CO ratios for the Bio-Rad HIV screening assay data and the distribution of S/CO values for samples with positive screening results were analyzed.

Keywords: False positive reaction; HIV-1; HIV-2; immunoassay; polymerase chain reaction; viral load.

Fig. 1

Distribution of S/CO ratios for Confirmed Positives and Non-True Positive Results. Note: 19 Bioplex specimens had S/CO ratios that exceeded 200 (plotted together at 200).

Fig. 2

Distribution of S/CO ratios of negative Bioplex screens.