Objective: Commercial TaqMan real-time PCR reagent was modified and applied on Light Cylcer 1.2 for quantifying HIV-1 RNA in plasma and compared with the reference method; COBAS AmpliPrep/COBAS Amplicor HIV-1 monitor test version 1.5.
Material and Method: Three hundred and eight frozen and fresh plasma samples were used for evaluation. Sequential specimens were also tested for follow-up cases.
Results: The correlation between HIV-1 RNA values obtained by reference and modified method with automated and manual sample preparation were significant with r = 0.916 and 0.908 (p < 0.001, p < 0.001) respectively with similar agreement log of mean bias (0.5 versus 0.48). High degree of correlation and agreement were observed between the assays in blind fresh plasma, r = 0.953 (p < 0.001) with 0.15 log difference in HIV-1 RNA level. Among follow-up samples, both methods gave 100% concordant results.
Conclusion: This modified protocol provided evidence for using modified commercial real-time PCR reagent for HIV-1 RNA quantitative detection as a monitoring tool for HIV/AIDS patients in Thailand.

Keywords: HIV-1 viral load, ARV monitoring: real-time PCR, Light Cycler