Editorial Commentary: Extending HIV Drug Resistance Testing to Low Levels of Plasma Viremia

Abstract

the variants in the circulation. Moreover, Food and Drug Administration (FDA)– approved HIV drug resistance genotyping platforms have specified application to specimens with >1000 copies HIV RNA/mL. Two companion papers in this issue of Clinical Infectious Diseases provide data from large clinical programs in British Columbia and central Italy to demonstrate that in fact the success rates for polymerase chain reaction (PCR) amplification to perform drug resistance testing in specimens from patients with 50–1000 copies HIV RNA/ mL plasma are both reasonably efficient and clinically predictive [6, 7]. Success rates were >90% for specimens >250 copies HIV RNA/mL in one study and for specimens >200 copies in the other. For specimens with detectable viral loads below these levels, successful sequencing results were still near 75%. In addition, the paper by Santoro et al showed that similarly successful rates were obtained with non-B subtype infections. Each of these studies provides a robust