Relative concentrations of HIV-1 variants resistant to nonnucleotide reverse transcriptase inhibitors by the oligonucleotide ligation assay (OLA). The following mutations were tested: (a) K103N, sequence AAC, (b) K103N, AAT, (c) V106M, ATG, (d) Y181C, TGY, and (e) G190A, GCA. Thresholds for 0%, 2%, 5%, and 20% of circulating mutant concentrations are based on optical density readings from OLA and logistic regression (see Materials and Methods section). Results are categorized by study arm and are cumulative across 2- and 6-week visits. Black triangles indicate specimens with no resistance mutations detected by consensus sequencing. Open circles represent specimens with resistance mutations detected by consensus sequencing. “X” indicates that the specimens were missing a consensus sequence or the OLA was indeterminate.