Recommendation for the execution of the oral glucose tolerance test for the diagnosis of diabetes mellitus [Raccomandazioni per l'esecuzione della curva standard da carico orale di glucosio (OGTT) per la diagnosi di diabete mellito]

The Oral Glucose Tolerance Test (OGTT) is a fractional method which measures the body's ability to metabolize glucose. Despite its large-scale use, the OGTT is still not appropriately performed in most of the Italian laboratories, as proven by our previous recent survey. In particular, we have provided evidence for the variability for execution of the OGTT in Italian laboratories indicating a poor tendency to standardise the procedures and the methodologies. These findings have been a stimulus to promote an effective Nationwide educational campaign, in order to standardise the procedures for the diagnosis of altered glucose metabolism and diabetes. The present document reports therefore the recommendations concerning the OGTT performed for the classification of diabetes. These recommendations do not apply to the execution of the OGTT during pregnancy for diagnosing gestational diabetes mellitus.