Frequency of false positive rapid HIV serologic tests in African men and women receiving prep for HIV prevention: implications for programmatic roll-out of biomedical interventions

Abstract

Background Rapid HIV assays are the mainstay of HIV testing globally. Delivery of effective biomedical HIV prevention strategies such as antiretroviral pre-exposure prophylaxis (PrEP) requires periodic HIV testing. Because rapid tests have high ( > 95%) but imperfect specificity, they are expected to generate some false positive results. Methods We assessed the frequency of true and false positive rapid results in the Partners PrEP Study, a randomized, placebo-controlled trial of PrEP. HIV testing was performed monthly using 2 rapid tests done in parallel with HIV enzyme immunoassay (EIA) confirmation fol- lowing all positive rapid tests. Results A total of 99,009 monthly HIV tests were performed; 98,743 (99.7%) were dual-rapid HIV negative. Of the 266 visits with

1 positive rapid result, 99 (37.2%) had confirmatory posi- tive EIA results (true positives), 155 (58.3%) had negative EIA results (false positives), and