Differences in rates of glycation (glycation index) may significantly affect individual HbA(1c) results in type 1 diabetes

Ten type I diabetic patients recorded their daily home blood glucose values , pre- and post-prandially, for 12 weeks. Blood was collected weekly for Hb A(1c) and total haemoglobin measurement. A rolling 28-day mean of all blood glucose values and a glycation index (the ratio of the HbA(1c) to the roll ing mean blood glucose) were calculated. In the pooled patients' data, ther e was a large scatter of results about the HbA(1c) versus mean blood glucos e regression line. There was less variation in the results of individual pa tients. The glycation indices showed marked inter-individual variation, and in 60% of patients there was an inverse relationship between glycation ind ex and mean blood glucose, suggesting a non-linear relationship between mea n blood glucose and HbA(1c). Patients should be monitored on the basis of t heir own previous results, and in some patients blood HbA(1c) may be a less sensitive index of mean blood glucose concentration at higher glucose leve ls.