BACKGROUND. Early infant diagnosis with rapid access to treatment has been found to reduce HIV-associated infant mortality and morbidity
considerably. In line with international standards, current South African guidelines advocate routine HIV-1 polymerase chain reaction
(PCR) testing at 6 weeks of age for all HIV-exposed infants and ‘fast-track’ entry into the HIV treatment programme for those who test
positive. Importantly, testing occurs within the context of increasing efforts at prevention of mother-to-child transmission (PMTCT) by
means of maternal and infant antiretroviral therapy (ART). In addition, infants already initiated on combination ART (cART) may be
retested with PCR assays for ‘confirmatory’ purposes, including assessment prior to adoption. The potential for cART to compromise the
sensitivity of HIV-1 PCR assays has been described, although there are limited and conflicting data regarding the effect of PMTCT regimens
on HIV-1 PCR diagnostic sensitivity.
METHODS. We describe a case series of three infants with different ART exposures in whom HIV diagnosis, confirmation or the result of
retesting for adoption purposes were uncertain.
RESULTS. These cases demonstrate that ART can be associated with a loss of detectability of HIV, leading to ‘false-negative’ HIV-1 PCR
results in infants on cART. Furthermore, current PMTCT practices may lead to repeatedly indeterminate results with a subsequent delay
in initiation of cART.
CONCLUSION. The sensitivity of HIV-1 PCR assays needs to be re-evaluated within the context of different ART exposures, and diagnostic
algorithms should be reviewed accordingly.