Performance of commonly used genotypic assays and comparison with phenotypic assays of HIV-1 coreceptor tropism in acutely HIV-1-infected patients

Objectives Although founder viruses in primary HIV-1 infections (PHIs) typically use the CCR5 coreceptor (R5-tropic), 3%–19% of subjects also harbour CXCR4-using viruses (X4-tropic), making tropism determination before CCR5 antagonist usage mandatory. Genotypic methods can be used to accurately determine HIV-1 tropism in chronically infected patients.