Comparison between a nucleic acid sequence-based amplification and branched DNA test for quantifying HIV RNA load in blood plasma.

HIV RNA was quantified in blood plasma from 209 patients and in control specimen comparing the NucliSens HIV-1 QT test (Organon Teknika), which is based on the nucleic acid sequence amplification procedure, and the Quantiplex 3.0 test (Bayer), which uses hybridization signal enhancement by branched DNA (bDNA) probes. A highly significant correlation (P=0.01) was found between the two methods with 88% of the samples showing similar results. In cases of discrepant findings, higher virus load was observed with either test (14xNASBA>bDNA; 12xbNDA>NASBA). Differences could neither be related to clinical features nor to divergent virus subtypes. Standard preparations containing 35000 and 222000 copies were quantified with intra-assay coefficients of variation of <20% using both methods. A preparation of 192 copies was measured with lower precision by both tests, yet was detected more reliably by the bDNA method.