Rational testing of the HIV-exposed infant

Objectives. The objectives of this study were 1) to evaluate testing regime ns of human immunodeficiency virus (HIV)-exposed infants and 2) to determin e optimal methods of follow-up by enzyme-linked immunosorbent assay (ELISA) testing. Methods. We reviewed the results from 742 HIV-exposed infants in the state of North Carolina; 2474 samples were tested for HIV by DNA polymerase chain reaction (PCR) at the University of North Carolina Retrovirology Core Labo ratory. We then reviewed the utility and costs of ELISA testing of all HIV- exposed infants who were seen at the Duke University Pediatric Infectious D isease Clinic between January 1, 1993, and May 5, 1998. We used likelihood ratios to model probability of HIV infection given 3 negative DNA (PCR) tes ts and to provide recommendations on the use of ELISA follow-up. Results. The overall sensitivity of the DNA PCR was 87.1%, and its specific ity was 99.9%. We evaluated 224 HIV-exposed infants who were seen at Duke U niversity and who had at least 3 negative diagnostic tests using either DNA PCR tests or HIV blood cultures. All 178 infants who subsequently underwen t ELISA testing ultimately demonstrated seroreversion. The Duke University Pediatric Infectious Disease Clinic transferred the care of 65 patients to primary care physicians before ELISA testing and retained the care of the r emaining 159 patients. Children who remained in Duke's care were more likel y to have documentation of seroreversion (158 of 159 vs 20 of 65). We revie wed costs of travel, physician appointment, and HIV antibody testing in a t ertiary care setting. Given 3 negative PCR tests, the expected cost per cas e of HIV detected by a positive ELISA assay is $23.8 million. Conclusions. Documentation of seroreversion in this cohort was nearly compl ete in the multidisciplinary subspecialty clinic but not when such responsi bility was left to the primary care physician. Given the low probability of disease in patients who have had 3 negative PCR tests, documentation of a negative ELISA may not be an appropriate use of medical resources.