DIRECT AND QUANTITATIVE DETECTION OF HIV-1 RNA IN HUMAN PLASMA WITH ABRANCHED DNA SIGNAL AMPLIFICATION ASSAY

Aim: To determine the relative effect of sample matrix on the quantita tion of HIV RNA in plasma. Method: Two HIV-positive specimens were dil uted into five and 10 different HIV-negative plasma samples, respectiv ely. Branched DNA signal amplification technology and reverse-transcri ptase polymerase chain reaction were used to measure the viral load. R esults: In one sample the viral load by polymerase chain reaction rang ed from undetectable to 1.9 x 10(5) copies/ml, and the branched DNA re sults ranged from 2.6 x 10(4) to 4.2 x 10(4) HIV RNA equivalents/ml. I n the other sample the corresponding figures were 6.3 x 10(4) to 5.5 x 10(5) copies/ml and 5.7 x 10(4) to 7.5 x 10(4) HIV RNA equivalents/ml . Conclusion: In contrast to reverse-transcriptase polymerase chain re action the branched DNA signal amplification assay does not require a separate extraction step or enzymatic amplification of the target. The refore this measurement is less affected by the sample matrix and the signal generated is directly proportional to the viral load.