Effect of the Use of Cholesterol Digitonide in Standards on the Results of Estimation of Cholesterol in Blood and Tissues by the Schoenheimer—Sperry Method

Abstract In the classic Schoenheimer—Sperry method for estimating cholesterol [J. Biol. Chem. 106, 745 (1934)] it is selectively precipitated with digitonin, and interference by other substances is minimized. The standards used in the color development are pure cholesterol. We suggest that the standard cholesterol should also be converted to cholesterol digitonide and treated identically to the test samples. When this is done, the values for cholesterol in test samples are significantly higher, both for free and total cholesterol in blood serum and for total cholesterol in tissues. Moreover, recovery experiments showed that error is diminished. Values for serum total cholesterol obtained when cholesterol digitonide standards were used were closer to those obtained by the method of Abell et al. than when pure cholesterol standards were used.