Determinación de la carga viral del VIH-1 en muestras de sangre seca en papel de filtro

Determination of HIV-1 viral load on dried blood spot specimens. The objective of this report was to evaluate dried blood spot as optional specimen for quantification of the viral load using Cobas®Ampliprep/Cobas® Taqman® HIV-1 Test for which RNA levels were quantified on 43 plasma and dried blood spot paired samples, collected from HIV-1 infected people. The Pearson linear correlation coefficient was calculated as well as the agreement by the Bland-Altman method. Studies regarding precision, linearity and analytical sensitivity of the assay were also carried out. In addition, the model from regression analysis was used to predict the plasma viral load. There was a high correlation in the viral load results in 39 out of 43 sample pairs studied (r = 0.964, p < 0.0001). The detection rate was 90.7 % and the test showed linear performance between 134 and 420 000 copies/mL of viral RNA. A good precision was obtained and it was demonstrated that there were no statistically significantly differences between predicted and real media values of the plasma viral load for a confidence level of 95 %. These results support the optional use of dried blood spot for the viral load determination with Cobas®Ampliprep/Cobas®Taqman® HIV-1 Test and it is suggest validating the model used with a greatest number of samples.