ACCURATE DETECTION OF MATERNAL ANTIBODIES TO HIV IN NEWBORN WHOLE-BLOOD DRIED ON FILTER-PAPER

Objective: The testing of neonatal blood specimens dried on filter pap er for maternal HIV antibodies, using an enzyme immunoassay (EIA) with confirmation of repeatedly reactive specimens by immunoblot (IB), was first described in 1987. It has been used to conduct large, unlinked, anonymous HIV seroprevalence surveys for surveillance of HIV in child -bearing women in several countries. We directly assessed the sensitiv ity and specificity of this combination of tests to detect maternal HI V antibodies. Setting: Serum samples obtained from mothers delivering at a major hospital in Kinshasa, Zaire were screened for HIV antibody using the rapid assay HIVCHEK. Design: Plasma from HIVCHEK-positive wo men and age-matched negative controls were tested by enzyme-linked imm unosorbent assay (ELISA); repeatedly reactive specimens were confirmed by Western blot (WB). Two days after delivery, whole blood was obtain ed from each newborn by heel-stick, dried on filter paper, and tested by EIA. Repeatedly reactive specimens were confirmed by IB. Main outco me measure. The serologic status of neonatal filter-paper specimens wa s compared with that of corresponding maternal plasma. Results: The te sting of neonatal filter-paper specimens using EIA, with confirmatory testing of repeatedly reactive specimens using IB, was 100.0% sensitiv e [of the 192 ELISA-positive and WB-positive maternal plasma specimens , 192 of the corresponding newborn filter-paper specimens were EIA-pos itive and IB-positive; 950/o confidence interval (CI), 98.1-100]. The detection of maternal HIV antibodies was 99.60/o specific using this c ombination of tests (of the 281 ELISA-negative or ELISA-positive but W B-negative maternal plasma samples, 280 of the corresponding newborn f ilter-paper specimens were EIA-negative or EIA-positive but IB-negativ e; 950/o CI, 98.0-100). Conclusions: Maternal HIV antibodies can be de tected accurately by testing neonatal blood dried on filter paper, usi ng EIA with confirmation of repeatedly reactive specimens by IB. This approach can facilitate the determination of HIV seroprevalence in chi ld-bearing women in countries with neonatal screening programs, or whe re serum or plasma is difficult to obtain.