Finding diabetes can help to decrease complications. It may also find a condition called prediabetes. This is a blood glucose level that is high but not yet diabetes. It will often move on to type 2 diabetes. Finding it early may help to prevent diabetes from starting.
Screening tests are given to people who may be at high risk.
American Diabetes Association (ADA) recommends screening for prediabetes and type 2 diabetes in the following:
Screening may be repeated again in 3 years.
The HbA1c test is a good indicator of your average blood glucose levels over the past 2-4 months. This test usually does not require any dietary restrictions.
|Diabetes||6.5% or higher|
With this blood test, you need to fast (not eat anything) for at least 8 hours before the test.
|Diagnosis||Fasting Plasma Glucose Level|
|Prediabetes||100-125 mg/dL (5.6-6.9 mmol/L)|
|Diabetes||126 mg/dL (7 mmol/L) or higher|
After fasting overnight, the doctor tests your glucose level. You are then asked to drink 75 grams of glucose dissolved in water. Two hours later, the doctor tests your glucose level again.
|Prediabetes||140-199 mg/dL (7.8-11 mmol/L)|
|Diabetes||200 mg/dL (11.1 mmol/L) or higher|
American Diabetes Association. Standards of medical care in diabetes-2018. Diabetes Care. 2018 Jan; 41(Suppl 1):S1-172 PDF. Available at:
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Accessed December 3, 2018.
Diabetes mellitus type 2 screening. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T113993/Diabetes-mellitus-type-2-in-adults. Updated November 12, 2018. Accessed December 3, 2018.
Prediabetes. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T181358/Prediabetes. Updated November 16, 2018. Accessed December 3, 2018.
8/2/2019 EBSCO DynaMed website. Available at: DynaMed Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T115153/Obesity-in-children-and-adolescents: American Diabetes Association. 2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2019. Diabetes Care. 2019;42(Suppl 1):S13-S28.
Last reviewed December 2018 by James P. Cornell, MD
Last Updated: 8/2/2019