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Diagnosis Endocrinology

Diabetes Mellitus

Your doctor will first ask about your medical history and perform a physical examination to check for symptoms of diabetes and high blood sugar. Diabetes usually is diagnosed with the following tests that measure the glucose levels in your blood:

  • Fasting Plasma Glucose Test This is the standard test for diagnosing type 1 and type 2 diabetes. You must not eat or drink anything for at least eight hours prior to this simple test in which blood is drawn to check your sugar levels. A diagnosis of diabetes will be made if you have a fasting blood sugar level of 126 milligrams per deciliter or higher on two separate days.
  • Other Tests Diabetes also may be diagnosed based on a random high glucose level of 200mg/dl and symptoms of the disease. Your doctor may wish to perform an oral glucose tolerance test, which is the traditional test for diabetes mellitus.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.