Determination of glucose in dried filter paper blood spots

A method for glucose determination in blood sampled by the patients outside hospital, is described and evaluated. Glucose in capillary blood spotted on filter paper (Schleicher& Schüll No. 2992), dried and stored at room conditions, is stable for at least 7 days. 6.5 mm discs, containing 10.3 microliter capillary blood are punched out from the spots and eluted in percloric acid. The glucose concentration in the eluate is determined by the glucose dehydrogenase method. Using duplicates, CV within assay is 3.6% between assay 4.2%. Mean recovery is 98.3%, SD 9.6%. Correlation to ordinary whole blood glucose dehydrogenase method is good, r = 0.984 (n = 244). The influence of blood spot variation, punching procedure, paper humidity and haematocrit has been examined. Results are compared to those of others, and advantages of the method are discussed.