Efficiency of reconstitution of immunoglobulin G from blood specimens dried on filter paper and utility in herpes simplex virus type-specific serology screening

The performance of studies using sera from remote locations is greatly facilitated if whole-blood samples dried on filter paper are shown to be compatible with the serologic assay being employed. Since dried blood samples do not require immediate refrigeration, occupy little space, and are easily transported, they may be used for evaluating the seroprevalence of herpes simplex virus type I (HSV-1) and HSV-2 in geographic locations where laboratory resources are limited. We evaluated the utility of dried blood samples for the detection of type-specific HSV antibodies. The efficiency of using immunoglobulin G (IgG) eluted from dried blood samples was found to be consistent with measurement of IgG concentrations in most corresponding serum samples. The ratio of the mean IgG concentration for all dried blood samples to the mean IgG concentration for the corresponding sera was 1:29. When the 1:29 ratio was applied to each of the 22 pairs of samples, there was a deviation of less than 15% between concentrations in the dried blood sample and in the corresponding serum sample in 19 of the pairs. No positive or negative bias was detected for the IgG eluted from dried blood. The presence of HSV-1 and HSV-2 antibodies was determined in the paired dried blood and serum samples, and no differences in the HSV serostatuses were detected for 43 of the 44 pairs. One pair's serostatus varied, with the serum sample being weakly positive for HSV-1 and the dried blood sample results being equivocal. The detection of HSV antibodies was generally consistent for dried blood samples stored frozen for over I year or at room temperature for 30 days, although decreased reactivities were found in a few samples.