The Clinical Value of Glycated Haemoglobin and Glycated Plasma Proteins

The biochemical diagnosis of diabetes mellitus and assessment of the management of diabetic patients have been based on measurement of blood glucose concentration under a variety of conditions since before the introduction of insulin therapy in 1922. The first clinically applicable method for the quantitation of blood sugar! and the earliest description of the blood sugar response to the ingestion of glucose? both date back to 1913. The aim of diagnosis and management of diabetic patients is twofold-to help patients avoid acute complications such as hypoglycaemia and ketoacidosis and to prevent the long-term complications of nephropathy, retinopathy, and atherosclerosis. The commonest cause of blindness in the young and middle-aged in the developed countries is diabetes mellitus, and premature death due to atherosclerosis or renal failure is much more frequent in diabetic than non-diabetic subjects. Although there is still no conclusive evidence as to the pathogenesis of these complications, it is likely that chronic hyperglycaemia plays a part.v' In practice the assessment of chronic hyperglycaemia by blood glucose measurements is virtually impossible because of the frequency with which measurements would be required, and because of the lability of blood glucose once appropriate insulin responses have been lost. The measurement of the non-enzymatically glycated derivatives of haemoglobin and plasma proteins has provided a reliable index of longterm blood glucose control of proven value to the management of patients. Despite serious consideration, however, their measurement has not been shown to be reliable in the diagnosis of diabetes mellitus.