<p>Ninety-two treatment naive HIV patients plasma were analysed by allele-specific PCR, detecting the two major NNRTI mutations K103N and Y181C in the reverse transcriptase gene. The limit of detection for the K103 mutations (AAC and AAT) is indicated by a dashed line. The limit of detection for the Y181C mutation (TGT) is indicated by a solid line. Crosses indicate two patients who died within three months. Shaded area indicates the assay background, which was determined as a mean Ct value from eight independent runs of 100% wild type template with mutant specific primers plus three standard deviations.</p