Rapid HIV Test May Help in Identifying Exposed Newborns

Major Finding: The results of a rapid HIV test performed on cord plasma or newborn blood were consistent with ELISA results in 54 neonates studied.

Data Source: A prospective study of the infants born to 14 mothers who were HIV positive and 40 mothers who were HIV negative.

Disclosures: None reported.

PHILADELPHIA — Rapid testing of umbilical cord or newborn blood quickly and reliably identified infants exposed in utero to HIV, according to Dr. Prabi Rajbhandari.

The rapid test was just as accurate as the standard enzyme-linked immunosorbent assay (ELISA), with 100% sensitivity and 100% negative predictive value in a small prospective study, Dr. Rajbhandari said at the annual meeting of the Eastern Society for Pediatric Research.

Time is of the essence for babies who have been exposed to the virus, Dr. Rajbhandari said in an interview. “The rapid test is complete in 20–30 minutes, compared to the ELISA, which can take days or even weeks to get a confirmed result,” Dr. Rajbhandari of the Bronx-Lebanon Hospital Center, New York, said in an interview. “This is a very important factor, because if we know the baby has been exposed, we can start interventions right away to prevent vertical transmission, with no danger of missing the critical period of intervention.”

None of the rapid HIV test kits have been studied in newborns. One kit, the OraQuick, has been approved for use in children as young as 12 years, but has not been studied in younger patients. None of the six rapid test kits has been studied using cord or newborn blood, she noted.

In New York, all pregnant women are offered HIV testing in the first trimester and, if living in an area of high HIV rates, again in the third trimester. If there is no record of the mother's HIV status at the time of labor, she is asked again to provide a blood sample. Infants of mothers who refuse that test can be tested for HIV exposure without consent. Abandoned newborns also are tested.

The prospective study by Dr. Rajbhandari and her associates included infants born to 14 HIV-positive mothers and 40 HIV-negative mothers. Test samples—blood collected at newborn screening, or cord plasma—were tested with the OraQuick test and ELISA.

For newborn blood, the tests showed perfect concordance for the exposed infants, she said. “The rapid test and the ELISA were both positive for all 14 samples from the positive mothers.”

There were 33 blood samples available for testing from the 40 infants from HIV-negative mothers; seven samples did not have enough blood for the additional test. Again, the rapid test and ELISA were in complete agreement, showing negative results for all 33 samples.

There were 11 cord blood samples available from HIV-positive mothers; all of these samples tested positive by both the rapid test and ELISA. The tests were also perfectly concordant with the 32 cord blood samples available for HIV-negative mothers.

An obvious limitation of the study is its small sample size, Dr. Rajbhandari noted. “We need to have a larger sample, and this study is ongoing in order to achieve that.”