HbA1c measurements have represented the gold standard for the evaluation of glycemic control in diabetic patients for more than 30 years. It is the best overall index of glycemic exposure thus far, and is even better than blood glucose in predicting the risk of chronic vascular complications, such as retinopathy, neuropathy, nephropathy and cardiovascular disease. Though, currently, HbA1c is widely accepted as an index of mean glycemia, a measure of risk for the development of diabetes complications, and a measure of the quality of diabetes care but there are number of factors, that can either falsely lower HbA1c test results or raise HbA1c test results independent of glycemia. Это и многое другое вы найдете в книге HbA1c: What all one wants to know (Dalia Rafat and Saif Khan)