Comparison of five methods for determination of 2,3 diphosphoglycerate in blood

Abstract

Because the importance of 2,3 diphosphoglycerate in the regulation of the oxygen affinity of hemoglobin is recognized, there is growing need for a suitable method for determining this metabolite. The colorimetric method of de Leeuw, 2 enzymatic rate dependent methods (of Nygaard and Rorth and of Loos and Prins), and 2 enzymatic end point methods (of Keitt and of Ericson and de Verdier) are compared. A good linearity was observed for all methods, up to 5.0 mmol of 2,3 diphosphoglycerate per liter of blood, except for the method of Ericson and de Verdier, for which an inexplicable upward drift in the calibration curve was found. Within run precision in the duplicates and long term precision in the methods of Loos and Prins and of de Leeuw were excellent. Mean analytical recoveries for all the methods ranged from 97 to 100%. In a paired comparison study of the methods, with the method of Loos and Prins as a reference, statistically significant differences were not found. Coefficients of correlation were better than 0.990 (P<0.0005).