NICE defines impaired glucose tolerance as a fasting plasma glucose less than 7.0mmol/L and a 2-hour venous plasma glucose (after ingestion of 75g oral glucose load) of 7.8–11.1mmol/L. Impaired fasting glucose is a level of 6.1–6.9mmol/L and HbA1c is considered increased at a level of 6.0–6.4%. Standard release preparations of metformin are not currently licensed for this indication.