Falsely elevated HIV-1 viral load results observed with Roche TaqMan HIV-1 v2.0 for samples stored frozen in Vacutainer plasma preparation tubes not observed with Abbott RealTime HIV-1

• Published in: Antiviral therapy 2013-01, Vol.18, p.A95-A95
• Main Authors: Cloherty, G, Swanson, P, Lucic, D, Dieckhaus, K, Anthony, P, Cataline, P, Herman, C, Hackett, J Jr, Skolnik, P, Chirch, L
• Format: Article
• Language: English
• Subjects: Human immunodeficiency virus 1
• ISSN: 1359-6535

BACKGROUND: Studies have demonstrated that plasma samples collected and stored frozen using Vacutainer plasma preparation tubes (PPT) may result in falsely elevated viral load (VL) values with the Roche COBAS TaqMan HIV-1 v1.0 test. This study was designed to compare VL results obtained for patient samples stored frozen in PPT using Roche COBAS TaqMan HIV-1 v2.0 test (CTM v2.0) and Abbott RealTime HIV-1 assay (RealTime HIV-1). METHODS: 349 samples from HIV-1-infected patients on HAART were collected and stored frozen in PPT. Samples were tested with CTM v2.0 and RealTime HIV-1. 63 samples with most discordant results (RealTime HIV-1 negative/CTMv2.0 positive) were further analysed using two nested RT-PCR assays targeting pol integrase: full-length (864 nt) and a highly conserved subregion (134 nt). RESULTS: 260/349 samples had VL values that differed by >0.5 log sub(10) copies/ml; 196 were detected by CTM v2.0 but not detected in RealTime HIV-1. 64 samples quantified by both assays had VL results differing by >0.5 log sub(10) copies/ml (0.6 to 2.2 log sub(10) copies/ml). Using two nested RT-PCR assays, HIV-1 RNA was not detected in the 63 discordant samples analysed (1.5-4.1 log sub(10) copies/ml) confirming RealTime HIV-1 results. CONCLUSIONS: In this study a high level of falsely elevated VLs were observed with the CTM v2.0 assay. This increase in reactivity was presumably caused by proviral DNA carryover captured by the CTM total nucleic acid extraction chemistry but not the RNA-specific extraction procedure used in RealTime HIV-1. The results suggest that using CTM with samples frozen in PPT could have significant clinical implications for HIV-1 patient management and confirms earlier findings that RealTime HIV-1 performance is not affected by PPT.