Comparative evaluation of the performance of the Abbott real-time human immunodeficiency virus type I (HIV-1) assay for measurement of HIV-1 plasma viral load following automated specimen preparation

The performance of the new Abbott real-time human immunodeficiency virus type 1 (HIV-1) assay for HIV-1 RNA load determination in plasma was compared to that of the Abbott LCx HIV-1 RNA quantitative assay following automated RNA isolation by the Abbott m1000 extractor. The measured viral loads of 89 clinical specimens differed by mean 0.19 log(10) copies/ml (95% confidence interval, 0.12 to 0.26 log(10) copies/ml). Although the difference in viral load determinations was positively skewed in favor of the LCx assay, it did not reach statistical significance (P = 0.42). Results were linearly associated (R-2 = 0.94) and strongly correlated (R = 0.96). Good performance was observed with HIV-1 subtypes other than B and circulating recombinant forms, although results obtained with two subtype G specimens and one H specimen showed a more substantial difference.