WHO manual for HIV drug resistance testing using dried blood spot specimens
Third edition
Overview
HIV-1 drug resistance (HIVDR) genotyping is an essential component of the WHO global HIVDR surveillance strategy. Plasma “gold standard” specimen type for HIVDR genotyping, but its use may not be feasible in rural, remote
areas in low- and middle-income countries, since preparing and storing it require personnel and laboratory infrastructure that are often lacking. An alternative specimen type is dried blood spots (DBS), which can be made without special
laboratory processing. DBS are more easily transported than plasma because they can be shipped at ambient temperature as non-hazardous materials using regular mail or courier services.
Despite the potential advantages of
DBS as a specimen type, there are several disadvantages, the foremost being the reduced sensitivity of viral RNA amplification, related to input specimen volume constraints. Viral RNA in DBS is susceptible to degradation if the
DBS are not kept desiccated or if they are left unfrozen for extended periods of time. Therefore, DBS for HIVDR genotyping must be handled differently than DBS for early infant diagnosis, which targets all nucleic acids, including
the more stable DNA component.
Several different methods for performing HIVDR genotyping using DBS have been developed and reported in the literature. This manual provides current best practice recommendations for laboratory HIVDR
testing using DBS. Emphasis is placed on specimen storage and processing, since these procedures might differ from those recommended for DBS collected for other purposes.
