Background: The 2021 update of the Centers for Disease Control and Prevention clinical guidelines for human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) recommended both antigen-antibody (Ag/Ab) and RNA testing at PrEP initiation and routine follow-up. We assessed the real-world use and performance of HIV tests among oral PrEP users.
Methods: An oral PrEP user cohort was constructed using the HealthVerity database that included linked diagnoses, laboratory tests, and prescriptions from December 2018 to August 2023. Data were stratified by pre-guideline update (2019-2021) and post-guideline update (2022-2023) periods. For each period, we assessed the agreement between same-day HIV Ag/Ab and RNA results and calculated the false-positive rates and positive predictive values of HIV Ag/Ab and RNA tests compared with the adjudicated HIV status.
Results: The HIV RNA testing rate for follow-up, per 100 person-years, increased from 16 before to 123 after the guideline update. The positivity rate of HIV RNA tests decreased from 1.39% to 0.22%. Overall agreement between Ag/Ab and RNA results remained high. The false-positive rates of HIV Ag/Ab and RNA testing remained similar, but the positive predictive value of HIV RNA testing for PrEP follow-up decreased from 100% to 67%. We estimated that 8226-9900 RNA tests would be needed for 1 HIV diagnosis earlier than would be detected with Ag/Ab testing alone.
Discussion: HIV RNA testing did not provide additional value to Ag/Ab testing during routine follow-up of oral PrEP users. Considering the cost and logistical complexity of HIV RNA testing, its use as a routine test during follow-up of oral PrEP users warrants reconsideration.
Keywords: HIV Ag/Ab testing; HIV RNA testing; oral PrEP; test performance.
Published by Oxford University Press on behalf of Infectious Diseases Society of America 2025.