Rapid Oral Fluid HIV Antibody Testing in Exposed Babies: A Diagnostic Study

Abstract

Aims: The usefulness of rapid oral fluid HIV antibody tests has rarely been evaluated in exposed babies. Study Design: A diagnostic survey comparing the performance of oral fluid HIV antibody test and the routine rapid blood screening test. Place and Duration of Study: University College Hospital, Ibadan and Nigerian Institute of Medical Research, Lagos, between May 2010 and April 2011. Methodology: The study involved children aged less than 18 months referred for screening in two large HIV care programmes in Nigeria using rapid antibody tests - an oral fluid test (Test A) and the routine blood test (Test B). The testing was blinded and HIV status was confirmed using DNA PCR. Results: A total of 94 children were studied with ages ranging from 0.13 to less than 18months. Out of the 94 parallel tests, when compared with DNA PCR, there were 7 (7.5%) discordant results. Test A gave one false positive, one false negative and no indeterminate result. Test B gave four false positive, one false negative and two indeterminate results. Test A had a sensitivity of 93.3%, specificity of 98.7%, positive predictive value of 93.3% and negative predictive value of 98.7% compared with Test B which had 90.0%, 92.9%, 60.0% and 98.7% respectively. Among the caregivers 88 (93.6%) preferred oral fluid testing to blood as it is painless and easy to perform. Conclusion: Compared with the rapid antibody blood test, the oral fluid test correlates better with DNA PCR in detecting the absence of infection in HIV exposed babies. Given this performance, it may be useful in expanding testing in HIV exposed children in settings where there are challenges with early infant diagnosis.