Field performance of the INSTI HIV-1/-2 antibody test in two South African antenatal clinics

This was a prospective study that assessed field performance of the INSTI HIV-1/-2 antibody test (INSTI test) in two antenatal clinics in South Africa (SA). INSTI test was evaluated against rapid tests used at these clinics, and pooled nucleic acid amplification testing (NAAT) performed for individuals with negative rapid tests. Three hundred and eighty-six pregnant women were enrolled; 334 (86.5%) with negative results on the screening rapid test, and 52 (13.5%; 95% confidence interval [CI]: 10.2–17.3%) with positive results on screening and confirmatory rapid tests. INSTI test yielded the same results as other rapid tests in all participants, thus showing a 100% sensitivity (95% CI: 93.2–100.0%) and specificity (95% CI: 98.9–100.0%). Pooled NAAT was performed for 290 participants who had negative rapid tests, and yielded negative results in all pools. These data show excellent field performance of the INSTI test, and highlight that this test can be implementedat SA clinics.