HbA1c measurement
- Correspondence to: Dr E S Kilpatrick Department of Clinical Biochemistry, Hull Royal Infirmary, Anlaby Road, Hull HU3 2JZ, UK; eric_kilpatrick{at}hotmail.com
- DCCT, Diabetes Control and Complications Trial
- IFCC, International Federation of Clinical Chemistry
- HbA1c, glycated haemoglobin
- UKPDS, United Kingdom Prospective Diabetes Study
As methods improve, inherent limitations become more apparent
It is difficult to overestimate the contribution made by glycated haemoglobin measurement (usually in the form of HbA1c) to the management of patients with diabetes mellitus and the reliance now placed on the test by clinicians. Before its introduction as a routine test in the late 1970s and early 1980s, objectively assessing glycaemic control relied on measures such as 24 hour urine glucose excretions1 and daily blood glucose profiles.2 By comparison, measurement of HbA1c gave a much more reliable measure of glucose control over the prolonged period of the previous six to eight weeks.3 The clinical usefulness of the test was cemented by major trials, such as the Diabetes Control and Complications Trial (DCCT) in type 1 diabetes4 and the United Kingdom Prospective Diabetes Study (UKPDS) in type 2 diabetes.5 Both showed that improved glycaemic control, as assessed by HbA1c, could lead to substantial reductions in the risk of developing the microvascular complication of diabetes such as retinopathy, nephropathy, and neuropathy. The UKPDS findings also suggested that the risk of myocardial infarction (the main cause of premature death in diabetes) could be improved by reducing HbA1c values.6
“The importance that is now placed on HbA1c is demonstrated by the new contract for general practitioners in the UK, which sets glycaemic control targets for diabetes patients”
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