Limitations in the laboratory diagnosis of vertically acquired HIV infection.

At present, the only well-standardized and widely available diagnostic techniques for HIV infection are detection of IgG HIV antibodies and HIV antigen. The antibody detection is sensitive, but is useful only in infants and children older than 15 months because of the presence of maternal antibodies. The utility of HIV antigen testing in neonates and young infants has not been established. A number of sensitive techniques, such as PCR, ELISPOT, and detection of HIV-specific IgM and IgA antibodies, are under development and promise to be very useful in the early diagnosis of vertical HIV infection. However, we will be able to accurately establish the sensitivity or specificity of the individual tests only when we have results of large prospective studies. These studies should compare different diagnostic methods and correlate the results of tests performed sequentially in neonates and young infants with the natural history of their disease process and eventual clinical outcome.