Blinded, multicenter quality control study for the quantification of humanimmunodeficiency virus type 1 RNA in plasma by the Belgian AIDS reference laboratories

Objective In order to evaluate the interlaboratory variation of HIV-1 RNA m easurements in plasma, the Belgian AIDS reference laboratories organized a blinded multicenter quality control study. Methods A test panel of coded spiked HIV-1 plasma samples reflecting the dy namic range of the assay was composed and distributed. The HIV-1 RNA concen tration of these samples was determined by the right Belgian AIDS reference laboratories by means of the Amplicor HIV-1 Monitor Version 1.5 assay. Results Analysis of the results demonstrated that there was little interlab oratory variation for the high concentration range (4.0-5.7 log(10) copies/ mL), never exceeding 0.2 log(10) copies/mL. However the standard deviation for the low concentration range (2.6-3.9 log(10) copies/mL) reached up to 0 .22 log(10) copies/mL. Conclusions Since interlaboratory variability never reached 0.5 log(10) cop ies/mL and each of the laboratories was able co detect four-fold difference s in plasma HIV-1 RNA levels, the Amplicor assay can be used in multicenter studies without a centralized analysis of samples. Furthermore, this well- characterized proficiency panel of spiked plasma samples could be used as a standard in the study of interassay comparisons.