| Category | Fasting plasma glucose before test | Plasma glucose 2 hours after ingestion of 1.75 g/kg glucose | Clinical outcomes |
| Normal glucose tolerance (NGT) | <100 mg/dL (5.6 mmol/L) | <140 mg/dL (7.8 mmol/L) | In general, clinically stable |
| Indeterminate glycemia (INDET) | <100 mg/dL (5.6 mmol/L) | <140 mg/dL (7.8 mmol/L), with a mid-point peak >200 mg/dL (11.1 mmol/L) | Clinical impact unclear but evidence suggests increased risk of morbidity |
| Impaired glucose tolerance (IGT) | <100 mg/dL (5.6 mmol/L) | 140 to 200 mg/dL (7.8 to 11.1 mmol/L) | |
| CFRD without fasting hyperglycemia | <126 mg/dL (7 mmol/L) | ≥200 mg/dL (11.1 mmol/L) | Increased morbidity and mortality |
| CFRD with fasting hyperglycemia | ≥126 mg/dL (7 mmol/L) | OGTT not necessary |
