Evaluation of three different commercial procedures for quantifying human immunodeficiency virus type-1 RNA levels

A branched DNA method for the quantification of human immunodeficiency virus type 1 (HIV-1) RNA levels (Quantiplex HIV RNA 2.0) was compared with a reverse transcriptase-coupled polymerase chain reaction method (Amplicor HIV-1 Monitor) and a nucleic acid sequence-based assay (Nuclisens HIV-1 QT) in plasma samples from a group of HIV-1 seropositive patients. We found a high correlation between Nuclisens and Quantiplex (r = 0.89; p < 0.001) and between Amplicor and Quantiplex (r = 0.94; p < 0.001), a shift of RNA viral load to higher Nuclisens and Amplicor values compared with the Quantiplex results and a significant positive correlation (rS = 0.60; p < 0.001) between the p24 antigen level and the RNA viral load determined with the Quantiplex assay. We also found higher sensitivities of the Nuclisens and the Amplicor procedures compared with the Quantiplex assay. The total sensivity of the Quantiplex assay in our study was 70% whereas that of the p24 antigen was only 29%.