Quantitation of hemoglobin A1a+b and hemoglobin A1c by automated "high-performance" liquid chromatography

The glycosylated hemoglobins A1a+b and A1c have been rapidly and precisely quantitated in 5-micro L samples of human blood hemolysate (approximately 240 micrograms of hemoglobin) by cation-exchange column chromatography. Total chromatographic is 22.0 min. Proportions of Hb A1c range from 3.85 to 6.71% in normal individuals and from 4.23 to 19.90% in diabetic subjects. Within-day variation was 1.58 and 1.10% for mean Hb A1c proportions of 4.92 and 10.32%, respectively. Hb A1c and Hb A1 are stable in hemolysates stored at 4 degrees C for as long as seven days, and indefinitely under liquid nitrogen.