Diagnosing diabetes

Diabetes is not diagnosed by the symptoms it causes. You must have a test to measure blood glucose to find out if you have diabetes.

Diagnosis Tests Tests A1c




126 mg/dL or higher on two occasions

200 mg/dL or higher (with symptoms)

6.4 percent or higher

Pre Diabetes

100-125 mg/dL (IFG: when your blood glucose is too high in the morning)

140-199 mg/dL (IGT: when your blood glucose is too high during the day)

5.7 to 6.3 percent


less than 100 mg/dL

less than 140 mg/dL

5.6 percent or less

IFG stands for impaired fasting glucose. IGT stands for impaired glucose tolerance.

Note: We used the word glucose instead of the word sugar so it does not get confused with the sugar in food.

Source: Allina Health's Patient Education Department, Basic Skills for Living with Diabetes, sixth edition
First Published: 11/27/2006
Last Reviewed: 10/23/2019