LAUSR

INTRODUCTION Dual human immunodeficiency virus/syphilis rapid diagnostic devices can play an important role in prevention efforts. The field performance of the INSTI Multiplex HIV-1/HIV-2/Syphilis Antibody Test (Multiplex) was evaluated. METHODS Fingerstick whole blood was tested using the rapid test. A fourth-generation HIV laboratory assay and treponemal-specific laboratory assays were used as reference. Rapid plasma reagin (RPR) was used to stratify treponemal results. Sensitivity and specificity were calculated. RESULTS Overall, 274 patients participated. Sensitivity of the Multiplex for detection of HIV was 98.8% (95% CI, 93.4-100%), and specificity was 100% (95% CI, 98.1-100%). Sensitivity for detection of syphilis antibodies was 56.8% (95% CI, 44.7-68.2%), and specificity was 98.5% (95% CI, 95.7-99.7%). Sensitivity for treponemal antibodies improved with increasing RPR and was 100% (95% CI, 78.2-100%) among samples with RPR titers ≥1:8. CONCLUSIONS The Multiplex showed excellent performance for detection of HIV antibodies and increasing sensitivity for detection of treponemal antibody with increasing RPR titer.