Lack of sensitivity of serologic testing for HIV in a mother-newborn pair

We report the birth of an enzyme-linked immunosorbent assay (ELISA)-negative baby to an ELISA- and Western blot-positive mother, raising questions about the validity of the mother's positive tests for HIV. There was no evidence of autoimmune disorders or progressive HIV infection in the mother, and polymerase chain reaction and other tests were negative. This rare case should alert physicians to a potential problem in diagnosing HIV infection in high-risk patients.