The influence of rapid changes in blood glucose on glycosylated hemoglobin measured by microcolumn and macrocolumn...

The effect of a rapid rise in blood glucose on glycosylated hemoglobin (HbA1) was measured by two different cation exchange chromatographic methods. Blood samples were taken after fasting and one hour after breakfast from 32 insulin treated diabetics for the measurement of 1) HbA1 with a microcolumn procedure with and without prior incubation of the samples in saline overnight and 2) HbA1 and HbA1c with the macrocolumn chromatographic method of Trivelli with and without prior dialysis of the hemolysates. Mean (+/- SEM) blood glucose concentration rose significantly one hour after breakfast from 9.8 +/- 0.8 mmol/l to 14.9 +/- 0.8 mmol/l (p less than 0.001). The corresponding HbA1-concentrations measured by microcolumn chromatography without incubation of the samples were 15.2 +/- 0.5% (fasting) of total hemoglobin and 15.8 +/- 0.6% (postprandial) (p less than 0.001) and after incubation 13.3 +/- 0.4% and 13.2 +/- 0.4%, respectively (NS). The HbA1-concentrations measured by the method of Trivelli without dialysis were 14.7 +/- 0.5% (fasting) and 14.9 +/- 0.5% (postprandial) (p less than 0.01) and after dialysis of the hemolysates 14.3 +/- 0.5% and 14.3 +/- 0.5%, respectively (NS). The HbA1c-concentrations measured by the macrocolumn method without dialysis were 11.1 +/- 0.4% (fasting) and 11.2 +/- 0.4% (postprandial) (p less than 0.05) and after dialysis 10.9 +/- 0.4% and 10.8 +/- 0.4%, respectively (NS). Acute hyperglycemia may cause an increase in HbA1-values determined by microcolumn chromatography, the magnitude of which can exceed 20% in an individual case. The acute effect can be abolished by incubation of the samples in saline overnight.