Table 1. Diagnosing Diabetes.
| Test | Results | Interpretation |
|---|---|---|
| HbA1c1 | ≥ 6.5% | Diabetes |
| 5.7-6.4% | Impaired glucose tolerance2 | |
| ≤ 5.7% | Normal | |
| Fasting Plasma Glucose3 | ≥ 126 mg/dL (7.0 mmol/L) | Diabetes |
| 100–125 mg/dL | Impaired glucose tolerance2 | |
| ≤100 mg/dL | Normal | |
| Two-hour plasma glucose during an OGTT4 | ≥ 200 mg/dL (11.1 mmol/L) | Diabetes |
| Random plasma glucose or patients with classic symptoms of hyperglycemia or hyperglycemic crisis | ≥ 200 mg/dL (11.1 mmol/L) | Diabetes |
| 140–199 mg/dL | Impaired glucose tolerance1 | |
| ≤ 140 mg/dL | Normal |
1
The test should be performed in a laboratory using a method that is NGSP certified and standardized to the DCCT assay.
2
Impaired glucose tolerance (IGT) is similar to impaired fasting glucose (IFG) but is diagnosed with a confirmed oral glucose tolerance test (OGTT). Both IGT and IFG are risk factors for future diabetes and for cardiovascular disease. They are sometimes jointly referred to as pre-diabetes. Group Health recommends avoiding the term pre-diabetes because not all patients with IGT and/or IFG will develop diabetes.
3
Fasting is defined as no calorie intake for at least 8 hours.
4
The test should be performed as described by the WHO using a glucose load containing the equivalent of 75 g of anhydrous glucose dissolved in water.