Screening and diagnosis of prediabetes: where are we headed?

It is currently estimated that more than 300 million people have impaired glucose tolerance (IGT), putting them at increased risk for type 2 diabetes mellitus (T2DM) and its adverse consequences. In addition, many others are at risk on the basis of a family history of T2DM, obesity, dyslipidaemia and hypertension. Screening for risk should include both blood glucose testing in high-risk populations and prescreening (e.g. by questionnaire, waist circumference measurement) to identify high-risk individuals in overall low-risk populations; these individuals should then undergo glucose testing. Fasting plasma glucose measurement cannot diagnose IGT; the preferred definite test for diagnosis is oral glucose tolerance testing.