Direct and quantitative detection of HIV-1 RNA in human plasma with a branched DNA signal amplification assay.

Aim: To determine the relative effect of sample matrix on the quantitation of HIV RNA in plasma. Method: Two HIV-positive specimens were diluted into five and 10 different HIV-negative plasma samples, respectively. Branched DNA signal amplification technology and reverse-transcriptase polymerase chain reaction were used to measure the viral load. Results: In one sample the viral load by polymerase chain reaction ranged from undetectable to 1.9×10 5 copies/ml, and the branched DNA results ranged from 2.6×10 4 to 4.2×10 4 HIV RNA equivalents/ml. In the other sample the corresponding figures were 6.3×10 4 to 5.5×10 5 copies/ml and 5.7×10 4 to 7.5×10 4 HIV RNA equivalents/ml