How is diabetes diagnosed?

Diagnosis of diabetes can be made based on any of the following test results, confirmed by retesting on a different day:

Normally, blood glucose levels stay within narrow limits throughout the day (4 to 8mmol/l). But they are higher after meals and usually lowest in the morning.

Fasting plasma glucose level ≥ 7.0 mmol/L (126 mg/dL). Fasting blood glucose level -- diabetes is diagnosed if higher than 126 mg/dL on two occasions. Levels between 100 and 126 mg/dL are referred to as impaired fasting glucose or prediabetes. These levels are considered to be risk factors for type 2 diabetes and its complications.

Oral glucose tolerance test -- diabetes is diagnosed if glucose level is higher than 200 mg/dL after 2 hours. (This test is used more for type 2 diabetes.)

Random (non-fasting) blood glucose level -- diabetes is suspected if higher than 200 mg/dL and accompanied by the classic diabetes symptoms of increased thirst, urination, and fatigue. (This test must be confirmed with a fasting blood glucose test).

Glycated hemoglobin (Hb A1C) ≥ 6.5%. this test has been used in the past to help patients monitor how well they are controlling their blood glucose levels. In 2010, the American Diabetes Association recommended that the test be used as another option for diagnosing diabetes and identifying pre-diabetes. Levels indicate:

• Normal: Less than 5.7%
• Pre-diabetes: Between 5.7% - 6.4%
• Diabetes: 6.5% or higher