Rapid Serological Tests Ineffectively Screen for HIV Exposure in HIV-Positive Infants

Brittany Urick, BA; Youyi Fong, PhD; Christopher Okiira, BSc; Nicolette Nabukeera-Barungi, MD; Denis Nansera, MD; Emmanuel Ochola, MD; Julius Nteziyaremye, MD; Victor Bigira, MD; Isaac Ssewanyana, BSc; Peter Olupot-Olupot, MD; Trevor Peter, PhD; Anisa Ghadrshenas, BSc; Lara Vojnov, PhD; Charles Kiyaga, BSc

Disclosures

J Acquir Immune Defic Syndr. 2018;77(3):331-336. 

In This Article

Methods

This was a cross-sectional prospective study of infants below the age of 2 years presenting at primary health facility entry points at 4 hospitals in Uganda. The 4 hospitals included were as follows: Mulago National Referral Hospital, St. Mary's Hospital Lacor, Mbale Regional Referral Hospital, and Mbarara Regional Referral Hospital. Infants were recruited from 6 facility entry points at each health care facility: immunization (Expanded Program on Immunization)/well-child clinic, pediatric outpatient, pediatric inpatient, nutrition ward, outreach, and PMTCT, which was the traditional EID testing setting. A statistically determined total sample size of 3600 infants aged younger than 2 years was included in the study. One hundred fifty infants were enrolled at each of the 6 entry points per hospital. Data collection occurred between September 2014 and August 2015.

Patients were systematically sampled and enrolled at each entry point. Because of low daily volumes (<16 infants/d), consecutive enrollment was used at the nutrition and PMTCT entry points. Systematic sampling across all attending patients was used within the immunization, pediatric outpatient, pediatric inpatient, and outreach settings because of high patient volume to ensure unbiased patient selection. It was predicted that each entry point could enroll 15 infants per day per study nurse; therefore, if an entry point typically had 16–30, 31–45, or 46–60 eligible infants per day, each study nurse would enroll every other, third, or fourth infant, respectively. Study systems were put in place to ensure that no infant was enrolled at multiple entry points. The study objectives and study enrollment processes, including pre-HIV test counseling, were explained to the mother or guardian of each infant invited to participate in the study at non-PMTCT entry points before they signed a letter of informed consent.

Demographic and clinical data were collected for each infant and mother (if present) using standardized study-specific forms and study-specific identification numbers. All enrolled infants underwent both serological and nucleic acid–based testing to determine HIV exposure and HIV infection status, respectively. Dried blood spot (DBS) specimens were collected for nucleic acid–based testing, and rapid serological tests using fresh capillary blood were conducted simultaneously for each patient. Both tests were conducted on each enrolled infant regardless of the respective results, except for infants at the PMTCT entry point who did not receive serological screening because their exposure status was already known. Health care facility staff and laboratory technicians were blinded to the test results of the other. Health care facility staff, including nurses, clinical officers, and laboratory technicians, were trained on study procedures, how to conduct DBS specimen collection, and rapid serological testing and demonstrated proficiency before study commencement.

Rapid serological testing was performed using the Alere Determine HIV-1/2 (Waltham, MA). One drop of whole blood was collected using a lancet heel stick, applied to the test strip, and tested per manufacturer's instructions. Either that same lancet heel stick or a fresh draw was used to collect an additional 3–5 drops of whole blood, which were applied to a filter paper card (Whatman 903; GE Healthcare Biosciences, Pittsburgh, PA). Specimens were dried for 4 hours or overnight at room temperature and shipped weekly for testing to the Central Public Health Laboratories in Kampala, Uganda. Dried blood spot specimens were processed and tested with the Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM 96) HIV-1 Qualitative Test (Roche Molecular Serologicals, Branchburg, NJ) according to the manufacturer's instructions.

Any infant with positive rapid serological test or nucleic acid–based test result were referred to PMTCT for posttest counseling of their mothers and inclusion in care and treatment per the national standard of care guidelines.

This study was approved by the Mildmay Uganda Research Ethics Committee, Uganda National Council for Science and Technology, Mulago Hospital Research and Ethics Committee, Institutional Review Committee at St. Mary's Hospital Lacor, and the Chesapeake Institutional Review Board in the USA.

Statistical analysis was performed with R statistical software (version 3.3.2; Free Software Foundation, Boston, MA) and GraphPad Prism (version 6.0; La Jolla, CA). Infants from similar entry points were pooled across hospitals for primary analyses. In addition, infants presenting to the PMTCT entry point did not receive a serological screen because their exposure status was already known, and thus were excluded from the analyses observing the performance of rapid serological tests to detect HIV exposure. Two-sample comparisons were performed using the nonparametric rank-based Wilcoxon–Mann–Whitney test and Fisher exact test for continuous and binary outcomes, respectively. Binomial probability confidence interval (CI)was computed using the Wilson method.[13]

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