Opinion is divided regarding whether to test all normal adults for diabetes. In general, people considered to be at higher risk for diabetes should undergo routine diabetes screening:

• Age: The American Diabetes Association (ADA) recommends that all adults over the age of 45 years be screened for diabetes every three years.
  
  
• High blood pressure and cholesterol: The U.S. Preventive Services Task Force recommends that adults with blood pressure of 135/80 or higher and those with dyslipidemia (high cholesterol) be screened for type 2 diabetes.
  
  
• Pregnancy: Diabetes which occurs only during pregnancy is known as gestational diabetes. In the U.S. it is common practice to screen for this condition between 24 and 28 weeks of gestation, by administering a glucose solution by mouth and checking the blood sugar one hour later. If this is abnormal, a formal three-hour glucose-tolerance test is performed.

Screening for diabetes usually involves obtaining a blood sugar reading after an overnight fast, also known as a fasting blood sugar. A blood sugar value over 126 mg/dL indicates type 2 diabetes. Ideal fasting blood sugar is less than 100 mg/dL.