SENSITIVITY AND SPECIFICITY OF A QUALITATIVE RNA DETECTION ASSAY TO DIAGNOSE HIV-INFECTION IN YOUNG INFANTS

Objective: To evaluate the sensitivity and specificity of an RNA detec tion assay for diagnosing perinatal HIV infection. Methods: Plasma and serum specimens taken during the first 3 months of life from HIV-infe cted and uninfected children enrolled in a cohort study were assayed f or HIV RNA using the qualitative nucleic acid sequence-based amplifica tion (NASBA) kit. Sensitivity, specificity, and predictive values were calculated. NASBA results from infected children were compared with D NA PCR results from the same blood samples. Autoantibody patterns of s uspected false-positive specimens were compared with those of subseque nt specimens from the same child to exclude specimen labelling errors. Results: Amongst 131 specimens from 105 HIV-infected children, the se nsitivity of the qualitative NASBA assay was 13 out of 34 [38%; 95% co nfidence interval (CI), 22-56] at < 7 days, 56 out of 58 (97%; 95% CI, 88-100) at 7-41 days, and 37 out of 39 (95%; 95% CI, 83-99) at 42-93 days of life. Of 252 specimens from 206 uninfected children, six teste d positive and one tested indeterminate by NASBA. Four of these positi ve specimens had discordant autoantibody patterns suggesting mislabell ing; excluding these, the test specificity was 245 out of 248 (99%; 95 % CI, 97-100). Amongst 128 paired specimens from infected children, NA SBA results were more often positive than those from DNA PCR (103 vers us 92; P = 0.01). Amongst infants with specimens drawn in the first we ek of life, the proportion born after > 4 h of membrane rupture was gr eater amongst those testing negative (81%) than those testing positive (46%; P = 0.05). Conclusions: The qualitative NASBA RNA assay is high ly specific and more sensitive than DNA PCR. Qualitative RNA assays ma y be useful for diagnosing and excluding perinatal HIV infection in ch ildren after the first week of life for such purposes as initiating an tiretroviral therapy and other treatment, resolving parental uncertain ty, determining timing of transmission, and providing endpoints for in tervention trials. (C) 1998 Lippincott-Raven Publishers.