[Determination of glutathione reductase activity in erythrocytes and whole blood as an indicator of riboflavin nutrition].

Recent developments in riboflavin statis assessment suggest the possibility of satisfactory replacement of the method based on the determination of glutathione reductase (GRe) (EC 1, 6, 4, 2) activity in erythrocytes by one on whole blood. The advantages would be the elimination of the steps of separation and washing of the erythrocytes, which may be of problematic execution under the difficult logistic conditions of field studies. In order to verify the interchangeability of the two methods, we have undertaken a comparison of the results obtained on 81 subjects. Our data show that the results of the whole blood method closely replicate those obtained on the erythrocytes and that all cases are correctly classified in terms of riboflavin status assessment. A linear regression analysis shows that the two methods overlap perfectly, with a highly significant (P less than 1%) correlation coefficient (r = 0.82). Sixty five percent of the variance of the dependent variable (CA GRsi) is accounted for by the variation of the independent variable CA GRe).