Revisiting screening for type 2 diabetes mellitus: the case for and against using HbA1c.

British Journal of General Practice, April 2015 e278 IntRoduCtIon Type 2 diabetes mellitus is a major cause of morbidity and premature mortality in the Western world. It is responsible for about 10% of the NHS spend (about £286/second in the UK). Of those diagnosed with type 2 diabetes, 25% are thought already to have evidence of complications indicating that the disease has been present for 4–7 years.1 Where people have been diagnosed with a ‘prediabetes’ condition, such as impaired fasting glycaemia or impaired glucose tolerance (IGT), a proportion still demonstrate evidence of microand macrovascular complications. Research has led to the hypothesis that early detection, particularly in the early stages of the disease, can reduce the incidence of complications. Many centres and professional bodies have adopted the recent guidance to utilise glycosylated haemoglobin (HbA1c) as a diagnostic tool for diabetes mellitus. Although HbA1c offers much potential in this regard, it is not yet entirely clear how it should be used in clinical practice in the context of existing tests.