False-positive rate of a "fourth-generation" HIV antigen/antibody combination assay in an area of low HIV prevalence

We retrospectively analyzed the performance of the Architect HIV antigen/antibody (Ag/Ab) combination assay in a tertiary health care center with a situation of low HIV prevalence. The specificity and positive predictive value (PPV) were 99.78% and 31.21%, respectively. However, the specificity and PPV could increase to 99.99% and 89.70% using an arbitrary cutoff value.