Haemoglobin A1c analysis in the management of patients with diabetes: from chaos to harmony.

Effective management of patients with diabetes mellitus requires accurate assessments of blood glucose control. The best characterised marker of long term glycaemic control is whole blood haemoglobin A(1c) (HbA(1c)). Published clinical trials have identified quantitative and direct relationships between the HbA(1c) concentration and risks of diabetic microvascular complications. However, in order to practice evidence-based medicine, assays used to measure patient samples should ideally produce values comparable to the assays used in these trials. Numerous assays using chromatographic and immunological detection methods are used around the world. This paper briefly reviews the scientific evolution of HbA(1c) and its analysis, discusses the reasons why HbA(1c) assay standardisation is a challenge, describes the approaches that have been adopted to harmonise HbA(1c) assays, and addresses the current initiatives to standardise HbA(1c) globally. These efforts have established HbA(1c) as an essential component in the management of patients with diabetes mellitus and are likely to lead to the use of HbA(1c) in the screening/diagnosis of diabetes.