Calculation of HbA1c and glycated albumin from serially measured self-monitored blood glucose in patients with type 1 diabetes mellitus.

BACKGROUND: Both HbA1c and glycated albumin (GA) values are influenced by weighted mean of preceding blood glucose levels depending on each half-life. Based on this principle, we developed formulas for calculation of HbA1c and GA using data from self-monitored blood glucose (SMBG). We also calculated HbA1c and GA in diabetic patients using the developed formulas. METHODS: This study included 9 patients with childhood-onset type 1 diabetes mellitus (6 males and 3 females; aged 11.4±4.2 y). From the weekly mean blood glucose (MBG) values obtained by the SMBG data during the previous 20 weeks, we calculated HbA1c and GA using the developed formulas and compared the calculated values with the measured values (n=42). RESULTS: The measured and the calculated values of HbA1c were 8.5±0.9% and 8.3±1.2%, respectively. The measured and the calculated values of GA were 24.9±3.7% and 26.4±4.0%, respectively. There were strong positive correlations between both values of HbA1c and GA (P<0.0001). CONCLUSIONS: The calculated HbA1c and GA values using the developed formulas from the SMBG data were generally in agreement with the measured values. Using the calculation formulas, the values of HbA1c and GA could be estimated from serially measured SMBG data.