2-​​h PG, 2-​​h plasma glucose; DCCT, Diabetes Control and Complications Trial; FPG, fasting plasma glucose; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; NGSP, National Glycohemoglobin Standardization Program; OGTT, oral glucose tolerance test; WHO, World Health Organization.  

*In the absence of unequivocal hyperglycemia, diagnosis requires two abnormal results from different tests, which may be obtained at the same time (e.g., A1C and FPG), or the same test at two different time points.
**For all three tests, risk is continuous, extending below the lower limit of the range and becoming disproportionately greater at the higher end of the range.