Determination of haemoglobin A_lc by iso-electric focusing. Effect of incubation of erythrocytes and comparison of results obtained by ion-exchange chromatography

Abstract

Blood samples from 24 non-diabetics and 26 diabetics were analysed using both thin layer iso-electric focusing and ion-exchange chromatography. Using iso-electric focusing it was found that about 10% of haemoglobin A_lc (0.7—1.2% of total haemoglobin) could be removed by a preceding incubation of the erythrocytes in saline at 37°C for 6 h. When glucose was added to the incubation medium in a final concentration of 25 mmol/l no decline was seen in the concentration of haemoglobin A_lc. Using similar treatment of erythrocytes identical results were obtained by the two methods. A reference interval for normal subjects (age range 6 months to 65 years) was established for the iso-electric focusing method using non-incubated samples.

Key Words:

• diabetics
• glucose
• heterogeneity
• rapid glycosylation
• reference values
• reversibility