Routine measurement of haemoglobin A1 at the diabetic outpatient clinic.

FOLLOWING the introduction of insulin therapy in 1922 one of the major problems in the long-term management of insulin-dependent diabetes was the lack of a convenient, reliable and objective test of longer term glycaemic control. In the 1960's and early 1970's haemoglobin A, (HbA,, glycosylated haemoglobin) was shown to be elevated, usually, in diabetic patients 1-3 and its biochemical structure was elucidated.4-6 The mid-1970's saw many reports confirming that measurement of HbA, provided an accurate and objective assessment of glycaemic control in the preceding 6 to 8 weeks, a period corresponding to the approximate half-life of the average red blood cell. The vast majority of these studies were either cross-sectional in design 7-10 or, if longitudinal, carried out in the controlled atmosphere of the clinical research centre or hospital ward.", 12