The relationship between blood glycosylated haemoglobin and home capillary blood glucose levels in diabetics.

Serial capillary blood glucose levels from insulin treated patients were recorded over 24 hour periods at fortnightly intervals for three months. Total glycosylated haemoglobin as % of HbA was measured at the end of this period by the Flückiger method, and % HbA1 by column chromatography. There were highly significant correlations between mean blood glucose levels over the three months and % HbA1 (r = 0.93, 95% confidence limits 0.84-0.98), and with total glycosylated haemoglobin (r = 0.88, 95% confidence limits 0.75-0.94). There was also a good correlation between results obtained by the two methods (r = 0.81, p less than 0.0001). There were less strong correlations between % HbA1 and blood glucose levels during each of the three months before the estimation, with percentage of glucose levels greater than 10 mmol/l and with mean fasting blood glucose. These data support the hypothesis that % HbA1 and total glycosylated haemoglobin are satisfactory measurements of short term diabetic control.