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Diagnosis?

Usually your doctor will do a blood test to determine whether or not you have diabetes or pre-diabetes. A diagnosis of diabetes can be made by several different tests. The following chart lists the tests used to diagnose diabetes.


Tests Used to Diagnose Diabetes.

  Fasting Blood Glucose Random Blood Glucose Oral Glucose Tolerance A1C
Normal Less than 100mg/dL   Less than 140mg/dL after 2 hours Less than 5.7%
Pre-Diabetes Greater than or equal to 100 and less than 126 mg/dL   Greater than or equal to 140 & less than 200mg/dL after 2 hours 5.7 - 6.4%
Diabetes Greater than or equal to 126mg/dL Greater than or equal to 200mg/dL w/ symptoms Greater than or equal to 200mg/dL after 2 hours Greater than or equal to 6.5%
Gestational Diabetes Greater than or equal to 95mg/dL (as part of OGTT)   Greater than or equal to 180mg/dL after 1 hour
Greater than or equal to 155mg/dL after 2 hours
Greater than or equal to 140mg/dL after 3 hours

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Results must be confirmed by repeat testing on a different day.

Brief Description of Tests:

  • Fasting Blood Glucose Test: Measured after you have not eaten for 8 hours.
  • Random Blood Glucose Test: Measurement is taken at any time, but must then be accompanied by the presence of symptoms to diagnose diabetes. A Random Blood Glucose test is taken anytime of the day without regard to food intake.
  • Oral Glucose Tolerance Test (or OGTT): Measurement of blood glucose level is taken after you have consumed a drink, containing 75 grams of glucose dissolved in water (100 grams are used to test for Gestational Diabetes).
  • A1C (or Hemoglobin A1C): Measurement of a person's average blood glucose level over the past 2 to 3 months. This test does not require fasting.

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American Diabetes Association

NDEP Partnership

Diabetes Guide