Rapid method for screening dried blood samples on filter paper for human immunodeficiency virus type 1 DNA

PCR is a highly sensitive method for the detection of human immunodeficienc y virus type. (HIV-1) nucleic acids in blood mononuclear cells and plasma. However, blood separation techniques require extensive laboratory support s ystems and are difficult when a limited volume of blood is available, which is often the case for infants. The use of blood samples stored on filter p aper has many advantages for the detection of perinatal HIV-1 infection, bu t current methods require extraction and purification of target DNA prior t o PCR amplification. We report a highly sensitive and rapid method for the extraction and detection of HIV-1 DNA in infant blood samples stored on fil ter papers. Because this rapid protocol does not involve steps for the remo val of potential inhibitors of the PCR, the highest sensitivity is achieved by testing the filter paper lysate in quadruplicate. Assays for HIV-1 DNA were done by using nested PCR techniques that amplify HIV-1 gag DNA from bl ood spot samples on filter paper and from corresponding viably frozen monon uclear cells separated from venous blood samples obtained from 111 infants born to HIV-1-seropositive mothers. PCR results with blood from filter pape rs showed 100% specificity (95% confidence internal [CI] 93.1 to 100%) and 96% (95% CI, 88.65 to 98.9%) and 88% (95% CI, 79.2 to 94.5%) sensitivity (f or quadruplicate and duplicate tests, respectively) compared to PCR results with blood mononuclear cells, Moreover, this method could detect HIV-1 seq uences of multiple subtypes.