Comparative effectiveness of dried plasma HIV-1 viral load testing in Brazil using ViveST for sample collection

BackgroundUtilization of dried plasma for HIV-1 viral load testing would significantly decrease sample shipping costs.ObjectivesTo describe the precision and reproducibility of ViveST® (ST) as a transportation method for shipping specimens for HIV-1 viral load (VL) testing.Study designThirty clinical plasma samples were used to generate replicate samples with HIV VL values of 4 log10, 3 log10 and 2 log10 copies/mL for reproducibility testing and an additional 299 samples with HIV VL <50 copies/mL (99); 1.7 log10 to 3.99 log10 (100); and 4 log10 to 5.99 log10/mL (100) were used to compare ViveST to frozen plasma samples using the VERSANT® HIV-1 RNA 3.0 Assay. Results were compared using Student t-test, Pearson correlation and Bland–Altman analyses.ResultsMean intra-assay variance among frozen and dried plasma triplicates was 0.15 log10 and 0.09 log10 copies/mL respectively (n = 10, P = NS). Compared to frozen plasma, there was a mean reduction of 0.3 log10, 0.27 log10, and 0.35 log10 copies/mL at the 4 log10, 3 log10, and 2 log10 copy/mL samples respectively (n = 30, all comparisons, P < 0.01). Overall correlation between 299 frozen and ViveST samples was r = 0.97, where 12 of 99 undetectable frozen VL were positive with ST, and 12 of 200 frozen detectable VL were undetectable with ViveST (mean VL 2.1, 1.9 log10 copies/mL respectively).ConclusionsHIV-1 viral load results using ViveST were reproducible, correlated well with frozen plasma, though yielding minimally lower values. Our data suggest that dried plasma for HIV-1 VL testing using ViveST has promise for use in HIV clinical practice.