Use of a dry-plasma collection device to overcome problems with storage and transportation of blood samples for epidemiology studies in developing countries

Studies are difficult in areas lacking modern facilities due to the inabili ty to reliably collect, store, and ship samples. Thus, we sought to evaluat e the use of a dry plasma collection device for seroepidemiology studies. P lasma was obtained by fingerstick using a commercial dry plasma collection device (Chemcard Plasma Collection Device) and serum (venipuncture) from in dividuals in Kazakhstan, Plasma samples were air dried for 15 min and then stored desiccated in foil zip-lock pouches at 4 to 6 degreesC and subsequen tly shipped to the United States by air at ambient temperature. Serum sampl es remained frozen at -20 degreesC until assayed. Helicobacter pylori statu s was determined by enzyme-linked immunosorbent assay (HM-CAP EIA) for the dry plasma and the serum samples. The results were concordant in 250 of the 289 cases (86.5%). In 25 cases (8.6%), the dry plasma samples gave indeter minate results and could not be retested because only one sample was collec ted. Five serum samples were positive, and the corresponding dry plasma sam ples were negative; one serum sample was negative, and the corresponding pl asma sample was positive. The relative sensitivity and specificity of the C hemcard samples to serum were 97.6 and 97.9%, respectively, excluding those with indeterminate results. Repeated freeze-thawing had no adverse effect on the accuracy of the test. We found the dry plasma collection device to p rovide an accurate and practical alternative to serum when venipuncture may be difficult or inconvenient and sample storage and handling present diffi culties, especially for seroepidemiologic studies in rural areas or develop ing countries and where freeze-thawing may be unavoidable.