Individual Variation in Fasting Blood Sugar.

The individual variation in fasting blood sugar was investigated in 4 healthy adults (2 women and 2 men), on successive days over a period of 3 weeks. The subjects were permitted to eat their usual diets. After a 12-hour fast, the blood was drawn by venepuncture.

Protein removal was effected, in the freshly drawn sample, by the Somogyi 1 zinc precipitation method. The glucose content of the filtrate was determined by the improved copper-iodometric titration of Shaffer. 2 All determinations were made in duplicate.

The data for each individual and for the group as a whole were analyzed statistically. The means, with the minimal and maximal values, standard deviations, and coefficients of variation, are presented in Table I.

The mean value is lower than that found by other methods, since it represents only the true glucose. The mean value found for the group of 42 individuals in the glucose tolerance study 2 was 83.12 ± 0.56 mgm. %.

The minimum and maximum values show a spread of 31.2, 12.6, 21.2, and 11.9 mg., for subjects 1, 2, 3, and 4, respectively. Since no attempt was made to keep the diet uniform for the 4 individuals, nor in the same individual from day to day, such differences were anticipated. The standard deviation for any subject does not differ significantly from that previously found in the earlier group of 42.2 The latter was 5.38 ± 0.40.