Screening and confirmation of human immunodeficiency virus type 1 infection solely by detection of RNA

Diagnosis of human immunodeficiency virus (HIV) infection by antibody-based testing allows for some recently infected individuals to be falsely assessed as non-infected. Since such individuals often have high viral loads and are capable of transmitting HIV, it is an imperative public health need to identify these individuals. We investigated the feasibility and capability of a diagnostic algorithm which included screening and confirmation of HIV infection using only nucleic-acid-based tests. This investigation involved screening 1361 prospectively collected specimens using antibody-based methods in parallel to simultaneously testing the same specimens by a qualitative HIV RNA detection method (APTIMA HIV-1). Specimens that were positive by antibody screening were confirmed by either immunofluorescent assay or Western blotting, while specimens positive by RNA screening were confirmed by real-time RT-PCR. In the course of the study, 27 specimens were found to contain either HIV antibody or HIV RNA. Twenty-six of the 27 specimens were HIV RNA positive, while 23 of the 27 specimens were antibody positive. One specimen was found which possessed HIV antibody but was assessed as negative by the HIV RNA screening test. Four specimens were found to contain detectable HIV RNA but were negative by the antibody screening test. Three of these four patients were negative at point-of-care by rapid test, while one was negative by enzyme immunoassay. These data indicate that screening and confirmation of HIV infection by RNA methods alone, if affordable, may constitute an effective alternative HIV diagnostic algorithm in certain settings.