Marcia M. Hobbs, M. Steiner, Kimberly D. Rich, Maria Gallo et al.
BACKGROUND: Prostate-specific antigen (PSA) is a valid biomarker of semen exposure in women and has been used to assess reliability of self-reported sexual behavior as well as serve as a proxy measure for condom efficacy. Quantitative PSA tests are expensive and require specialized equipment. A simp...