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Who Should Be Tested for Diabetes, and How is Diabetes Diagnosed?

Diabetes is diagnosed using one of four simple blood tests in a doctor’s office or health clinic. The tests measure your blood-glucose level, which means the amount of sugar in your blood. Many people with diabetes do not have symptoms so it is important to get tested if you have risk factors for the disease.

Who Should Be Tested For Diabetes
The American Diabetes Association recommends blood tests for diabetes in any person with symptoms of the disease. In people without symptoms, testing should begin at age 45 and every three years thereafter or earlier in adults who are overweight or obese—meaning a body mass index (a measure of body fat) ≥25 kg/m2—and have any of the following other risk factors:

  • Parent or sibling with diabetes
  • Physical inactivity
  • African American, Hispanic American, Native American, Asian American, or Pacific Islander
  • Women who had gestational diabetes or who gave birth to a baby weighing more than 9 pounds
  • HDL (high-density lipoprotein) cholesterol level ≤35 mg/dL
  • Triglyceride level ≥250 mg/dL
  • High blood pressure (hypertension)
  • Polycystic ovarian syndrome
  • Impaired glucose tolerance or impaired fasting glucose (also known a pre-diabetes) on previous blood-glucose  testing
  • History of heart disease

In children and adolescents, testing for type 2 diabetes should be considered for those who have diabetes symptoms or who are overweight and have two of the following risk factors:

  • Family history of type 2 diabetes in a first- or second-degree relative
  • Native American, African American, Latino, Asian American, Pacific Islander
  • Signs of prediabetes such as acathosis nigricans (skin pigment condition), hypertension, dyslipidemia (elevated cholesterol and/or triglycerides), polycystic ovarian syndrome, or small-for-gestational-age birth weight
  • Mother with a history of diabetes or gestational diabetes

Testing in children should begin at age 10 or when the child enters puberty and should be repeated every 3 years.

BMI and Racial/Ethnic Groups
Some studies suggest that testing should be considered in people with a lower body mass index (BMI) who are of certain racial/ethnic groups, such as people of South Asian, Chinese, and African American descent. Talk to your doctor to see if you should be tested for diabetes.  

Tests Used to Diagnose Diabetes
The Table shows the types of blood tests used to diagnose diabetes and how they are performed. Typically, diabetes is diagnosed if test results are positive when tested on two separate days.

Table. Tests Used to Diagnose Diabetes

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The Diabetes Center