Screening for Type 2 Diabetes

The purpose of screening is early diagnosis and treatment. Screening tests are usually administered to people without current symptoms, but who may be at high risk for certain diseases or conditions.

Screening Tests

Random Plasma Glucose Test—As part of your routine physical exam, your doctor may draw some blood to check your liver, kidney, and endocrine functions, including blood glucose. This blood is taken any time of day, without regard to when you have last eaten. A measure of 200 milligrams per deciliter (mg/dl) [11.1 mmol/L] indicates that you may have diabetes. In this case, your doctor will do further testing to determine if you have diabetes.

Health Fair Screening—Blood glucose testing is often done at health fairs as well. Here, you will need to give only a few drops of blood from your fingertip, and you'll have results within a few minutes. If the results indicate that your blood glucose level is high, you should see your doctor for further testing.

See the diagnosis page for a description of the further testing your doctor will do.

Screening Guidelines

It is estimated that 16 million Americans have "prediabetes," which is also called impaired glucose tolerance. This condition is characterized by high blood glucose levels that aren't high enough to be diagnosed as diabetes. However, the condition often progresses to type 2 diabetes.

In order to detect prediabetes and take steps to prevent its progression to type 2 diabetes, the American Diabetes Association and the National Institutes of Health recommend the following:

  • Screening should be considered in people over the age of 45.
  • Screening is strongly recommended for people over the age of 45 who are overweight with a body mass index (BMI) over 27.
  • Screening should also be considered for people younger than 45 if they are significantly overweight and have another risk factor, such as:
    • First-degree relative (mother, father, brother, or sister) with a history of diabetes
    • History of gestational diabetes, or gave birth to a baby weighing more than nine pounds
    • Belonging to a high-risk group: African American, Hispanic American, Pima Indian, Native American, Asian American, or Pacific Islander
    • High blood pressure (over 140/90 mmHg) or low level of “good cholesterol" or HDL ( less than 40 mg/dL [1.0 mmol/L]) or high triglycerides (more than 200 mg/dL [2.3 mmol/L]).

Screening for diabetes in these cases is part of an overall approach to reduce the risk of heart disease in people with these risk factors.


Agency for Healthcare Research and Quality. Task force issues two recommendations on diabetes screening for adults and pregnant women [news release]. February 3, 2003.

American Diabetes Association website. Available at: http://www.diabetes.org . Accessed February 8, 2006.

Gillis CL, Abrams KR, Lambert PC, et al. Pharmacological and lifestyle interventions to prevent or delay type 2 diabetes in people with impaired glucose tolerance: systematic review and meta-analysis. Brit Med J. 2007;334:299-302.

Harris R, Donahue K, Rathore SS, et al. Screening adults for type 2 diabetes: a review of the evidence for the US Preventive Services Task Force. Ann Intern Med . 2003;138(3):215-229.

US Preventive Services Task Force. Screening for type 2 diabetes mellitus in adults: recommendations and rationale. Ann Intern Med . 2003;138(3):212-214.

Last reviewed April 2007 by David Juan, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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