Diagnostic accuracy of oral mucosal transudate tests compared to blood-based rapid tests for HIV among children ages 18 months to 18 years in Kenya and Zimbabwe

Background: Gaps persist in HIV testing for children who were not tested in prevention of mother-to-child HIV transmission programs. Oral mucosal transudate rapid HIV tests (OMT) have been shown to be highly sensitive in adults but their performance has not been established in children. Methods: ART-naive children aged 18 months to 18 years in Kenya and Zimbabwe were tested for HIV using rapid OraQuick ADVANCE Rapid HIV-1/2 Antibody test on oral fluids (OMT) and blood-based rapid diagnostic testing (BBT). BBT followed Kenyan and Zimbabwean national algorithms. Sensitivity and specificity were calculated using the national algorithms as the reference standard. Results: A total of 1,776 children were enrolled; median age was 7.3 years (IQR: 4.7, 11.6). Among 71 children positive by BBT, 71 were positive by OMT (sensitivity: 100% [97.5%CI: 94.9-100%]). Among the 1,705 children negative by BBT, 1,703 were negative by OMT (specificity: 99.9% [95%CI: 99.6-100.0%]). Due to discrepant BBT and OMT results, 2 children who initially tested BBT negative and OMT positive were subsequently confirmed positive within 1 week by further tests. Excluding these 2 children, the sensitivity and specificity of OMT compared to BBT were each 100% (97.5%CI: 94.9-100% and 99.8-100%, respectively). Conclusions: Compared to national algorithms, OMT did not miss any HIV-positive children. These data suggest that OMTs are valid in this age range. Future research should explore the acceptability and uptake of OMT by caregivers and health workers to increase pediatric HIV testing coverage.