Role of the Laboratory in Ensuring Global Access to ARV Treatment for HIV-Infected Children: Consensus Statement on the Performance of Laboratory Assays for Early Infant Diagnosis

Abstract

A two day meeting hosted by the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) was held in May 2006 in Entebbe, Uganda to review the laboratory performance of virologic molecular methods, particularly the Roche Amplicor DNA PCR version 1.5 assay, in the diagnosis of HIV-1 infection in infants. The meeting was attended by approximately 60 participants from 17 countries. Data on the performance and limitations of the HIV-1 DNA PCR assay from 9 African countries with high-burdens of HIV/AIDS were shared with respect to different settings and HIV- subtypes. A consensus statement on the use of the assay for early infant diagnosis was developed and areas of needed operational research were identified. In addition, consensus was reached on the usefulness of dried blood spot (DBS) specimens in childhood as a means for ensuring greater accessibility to serologic and virologic HIV testing for the paediatric population.

HIV Diagnostics: Challenges and Opportunities

“…When they arrive at the clinic or laboratory, the filter paper samples are placed in a lysis buffer to release the targets of interest (i.e., antibody, antigen or nucleic acid) into solution for ana lysis. DBS testing has proven to be effective in diagnosing HIV [28,[41][42][43], but drawbacks of this approach include reduced sample recovery owing to nonspecific binding to the membrane (reducing sensitivity), possible decomposition of critical biomarker molecules after long storage times (reducing sensitivity) [29], and potential losses to follow-up because a diagnosis is not given to the patient at the time of the visit. Efforts aimed at building up local health programs and infrastructures would expand access to DBS testing services.…”

“…Infants cannot be tested accurately using antibody-detecting assays until they are 18 months of age because the presence of maternal PersPective | Wong & Hewlett antibodies could mask their true HIV status [28]. The current standard of care is to start the newborn on ART while performing DNA NAT at 2 and 4 weeks of age, with two negative test results being a confirmation of no transmission [44].…”

“…Frequent monitoring would be needed for breastfeeding infants since transmission can occur through breast milk [45]. Standard practices in RLS include observing the onset of clinical symptoms as indicators of HIV status and preparing DBS to be transported to a laboratory for NAT or an ELISA [28]. There are ultra-sensitive p24 assays that are almost as sensitive as NAT under certain conditions for pediatric testing and monitoring [46]; however, similar to NAT, the reagent requirements for p24 assays may pose logistical problems.…”

“…There are ultra-sensitive p24 assays that are almost as sensitive as NAT under certain conditions for pediatric testing and monitoring [46]; however, similar to NAT, the reagent requirements for p24 assays may pose logistical problems. There are algorithms that describe the use of rapid tests in infants under 18 months of age based on evidence that there is a correlation between a negative rapid test result and a negative test result by molecular assays [28], and this could be an alterative when other tests are unavailable.…”

“…Moreover, NAT assays and ELISAs are suboptimal in RLS because many of those in need of testing live in remote locations with limited access to clinics. The use of portable, rapid tests for decentralized PoC testing in remote areas and shipment of dried-blood spot (DBS) samples collected on filter paper to clinics for testing have been effective in diagnosing HIV infection, however [28,29].…”