Background: New automated and ultrasensitive assays are becoming available to monitor HIV-1 plasma viral load, which is an essential market for the clinical follow-up. Objectives: To evaluate the performances of the VERSANT (R) HIV-1 RNA 1.0 (kPCR) automated assay in a clinical laboratory setting. Study design: Frozen plasma samples from various HIV-1 subtypes, previously analysed with the VERSANT (R) HIV-1 RNA 3.0 (bDNA) in clinical routine, were retested with the new VERSANT (R) kPCR assay. A comparison was also done with two other commercial assays (NucliSens EasyQ (R) HIV-1 and Abbott real time (TM) HIV-1). Results: We observed a good correlation between the viral load measurements obtained with the kPCR assay and the other techniques. Nevertheless, in terms of absolute quantification, we observed discrepancies of more than 0.5 log cop/ml plasma with 36%, 35% and 0% of the samples respectively with NucliSens EasyQ (R), VERSAN (R) bDNA 3.0 and Abbott real time (TM). No HIV-1 negative sample was amplified by the kPCR. Tenfold dilutions of samples from HIV-1 subtypes A-D, F-H, K, CRF01, CRF02 and CRF06 were analysed to evaluate the kPCR efficiency: the amplification had an efficiency close to the maximum of 2 for each of the subtypes tested. Conclusions: The VERSAN (R) HIV-1 RNA 1.0 assay (kPCR) is suitable for use in a clinical setting with various HIV-1 subtypes. The plasma viral load quantifications obtained with the kPCR assay were close to those obtained with the Abbott real time (TM) HIV-1 assay. (C) 2009 Elsevier B.V. All rights reserved.