Fast fraction haemoglobin (HbA1) in the assessment of diabetes control.

The degree of control of 132 diabetic patients was assessed using historical data, urine glucose and blood glucose measurements. These were then related to HbA1, taken as the final arbiter of glycaemic control. Symptoms of hyperglycaemia and glycosuria were found to be not sensitive or specific indices of control, though symptomatic glycosuric patients tended to have higher HbA1. Fasting blood glucose correlated modestly with HbA1 (r = 0.60, p less than 0.001) but if used alone to determine degree of control, 21% and 9% of patients could be expected to be over or under assessed respectively. The assessment value of timed post-breakfast blood glucose applied only to 120 and 150 minutes post-breakfast blood glucose as they correlated well with HbA1 (r = 0.73, p less than 0.001 and r = 0.96, p less than 0.001 respectively). Clinically impression of degree of control based on a combination of historical data, urine glucose and blood glucose led to "undertreatment" in 41% and "overtreatment" in 27% of patients. The complementary value of a knowledge of HbA1 was thus highlighted.