[Clinical usefulness of measurement of creatine contents in human erythrocytes as an index of erythropoiesis].

The apparent half-life of erythrocytes in human blood have usually been measured using 51Cr or 32P-labeled erythrocytes. However, these methods are not suitable for routine methods for the determination of the half-life of erythrocytes because of requirement for both patient admission and complicated procedure. In 1967 Griffiths and Fitzpatrick suggested that creatine level in human packed erythrocytes reflected the mean-age of erythrocyte population. Fehr and Knob reported that erythrocyte creatine levels correlated closely with half-life of erythrocytes by means of 51Cr in severe and milder hemolytic anemias. In order to verify the clinical usefulness of measurement of creatine contents in human erythrocytes as an index of erythropoiesis, the number of reticulocytes counted by an automated reticulocyte counter (R-3000, Toa medical instruments) and creatine contents in erythrocytes measured by high performance liquid chromatography were compared. To evaluate the erythropoietic dynamics, we tried to determine the frequency distribution for individual erythrocyte cell age using erythrocyte creatine. The effect of erythrocyte life-span on hemoglobin A1c(HbA1c) was also appraised in normal blood sugar subjects. A significant increase (p less than 0.005) of erythrocyte creatine was found both in inactive autoimmune hemolytic anemia (AIHA) and in active AIHA. In severe AIHA, the frequency distribution of erythrocyte creatine shifted to the area of high level erythrocyte creatine, and showed a broad-pattern form corresponding to erythropoiesis. Negative correlation (r = -0.707, p less than 0.005) was revealed between erythrocyte creatine and HbA1c in normal blood sugar subjects.(ABSTRACT TRUNCATED AT 250 WORDS)