Quantification of HIV-1 group M (subtypes A-G) and group O by the LCx HIV RNA quantitative assay

Human immunodeficiency virus type 1 (HIV-1) genetic diversity presents a ch allenge to nucleic acid-based assays with regard to sensitivity of detectio n and accuracy of quantification. The Abbott LCx HIV RNA Quantitative assay (LCx(R) HIV assay), a competitive RT-PCR targeting the pol integrase regio n, was evaluated using a panel of 297 HIV-1 seropositive plasma samples fro m Cameroon, Uganda, Brazil, Thailand, Spain, Argentina and South Africa. Th e panel included group M subtypes A-G, mosaics, and group O based on sequen ce analysis of gag p24, pol integrase, and env gp41. The LCx HIV assay quan tified 290 (97.6%) of the samples, including all the group O samples tested . In comparison, the Roche AMPLICOR HIV-1 MONITOR test versions 1.0 and 1.5 quantified 67.3 and 94.6% of the samples, respectively. No group O specime ns were quantified by either version of AMPLICOR HIV-1 MONITOR. Seven speci mens were below the detectable limits of all the three assays. The LCx HIV assay had fewer nucleotide mismatches at primer/probe binding sites as comp ared with both AMPLICOR HIV-1 MONITOR tests. The high degree of nucleotide conservation within the pol target region enables the LCx HIV assay to effi ciently quantify the HIV-1 subtypes A-G and the most genetically diverse HI V-1, group O. (C) 2000 Elsevier Science B.V. All rights reserved.