We evaluated the Standard Q HIV/Syphilis Combo Test (SD Biosensor, South Korea), a dual rapid test using stored sera (N = 400) in a laboratory setting in Lima, Peru. The sensitivity and specificity for HIV antibody detection was 100.0% (95% CI: 98.2–100.0%) and 99.5% (95% CI: 97.2–100.0%), respectively. For treponemal antibody detection the sensitivity and specificity was 97.5% (95%CI:94.3–99.2%) and 100.0% (95%CI:98.2–100.0%), respectively.