Establishment of mail medical examination system using immediate plasma separating device by the self-collection blood--the method of dilution ratio calculation by using Internal standard for the sample with different amount of collecting blood

A method of calibrating unquantified samples was developed in order to conduct tests from approximately 65 microl or less of self-collected whole blood from the finger. In this method, the dilution ratio is estimated by absorption analysis of an internal standard substance in the blood dilution buffer. Good results for replication of the dilution ratio were obtained, with a CV value of 0.99-2.78% and a rate of concordance with the theoretical dilution ratio of 99.4-99.8%. Evaluations of the utility of this system (Demecal System) were performed using total cholesterol measurement, and excellent correlation with the measurement value in plasma was achieved, with a correlation coefficient of r=0.975 at n=40 and a regression equation of y=1.02x-2.83. Dilution of 7-fold or less is required to assure accuracy with this system.