HIV-1 Nucleic Acids Identify Rectal HIV Exposures in Self-Collected Rectal Swabs, Whereas Y-Chromosome Single Tandem Repeat Mixtures Are Not Reliable Biomarkers of Condomless Receptive Anal Intercourse.

YSTR mixtures demonstrated 80% specificity but only 30% sensitivity as a biomarker of CRAI in self-collected rectal swabs. However, detection of HIV-1 exposures in self-collected swabs may help in identifying those needing further HIV risk reduction strategies.