1997 ADA criteria (4) for IFG, IGT, and diabetes
| Condition | Fasting plasma glucose (mg/dl) | Test and values 2-h OGTT (mg/dl) | HbA1c (%) |
|---|---|---|---|
| Normal | ≤109 | ≤139 | NA |
| IFG | 110–125 | NA | NA |
| IGT | NA | 140–199 | NA |
| Diabetes | ≥126 | ≥200 | Variable |
IFG is preferred to IGT by the ADA because of its greater convenience, but IFG and IGT are regarded as equivalent. The ADA recommends against use of HbA1c as a diagnostic test for diabetes. HbA1c threshold for diabetes is variable, but typically between 6.1 and 7.0%. No HbA1c values are recognized as equivalent to IGT or IFG.