Criteria for Diagnosing Diabetes

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Topic Overview

To be diagnosed with diabetes , you must meet one of the following criteria: footnote 1

  • Have symptoms of diabetes (increased thirst, increased urination, and unexplained weight loss) and a blood sugar level equal to or greater than 200 milligrams per deciliter (mg/dL). The blood sugar test is done at any time, without regard for when you last ate (random plasma glucose test or random blood sugar test ).
  • Have a fasting blood sugar level that is equal to or greater than 126 mg/dL. A fasting blood sugar test (fasting plasma glucose) is done after not eating or drinking anything but water for 8 hours.
  • Have a 2-hour oral glucose tolerance test (OGTT) result that is equal to or greater than 200 mg/dL. An OGTT is most commonly done to check for diabetes that occurs with pregnancy (gestational diabetes).
  • Have a hemoglobin A1c that is 6.5% or higher. (This test is most reliable for adults. Some experts recommend using one of the other tests to diagnose diabetes in children. footnote 2 )

Your doctor may repeat the test to confirm the diagnosis of diabetes.

If the results of your fasting blood sugar test are between 100 mg/dL and 125 mg/dL, your OGTT result is between 140 to 199 mg/dL (2 hours after the beginning of the test), or your hemoglobin A1c is 5.7% to 6.4%, you have prediabetes . This means that your blood sugar is above normal but not high enough to be diabetes. Discuss with your doctor how often you need to be tested. footnote 1

References

Citations

  1. American Diabetes Association (2014). Diagnosis and classification of diabetes mellitus. Diabetes Care, 37 (Suppl 1): S81-S90. DOI: 10.2337/dc14-S081. Accessed April 27, 2017.
  2. American Diabetes Association (2017). Standards of medical care in diabetes-2017. Diabetes Care, 40(Suppl 1): S1-S135.

Credits

ByHealthwise Staff

Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine

Kathleen Romito, MD - Family Medicine

Adam Husney, MD - Family Medicine

Specialist Medical Reviewer Matthew I. Kim, MD - Endocrinology, Diabetes and Metabolism

David C. W. Lau, MD, PhD, FRCPC - Endocrinology

Current as ofDecember 7, 2017