Symptoms:

High blood sugar levels can cause several symptoms, including:

• Blurry vision
• Excess thirst
• Fatigue
• Frequent urination
• Hunger
• Weight loss

Because type 2 diabetes develops slowly, some people with high blood sugar have no symptoms.

Symptoms of type 1 diabetes develop over a short period of time. People may be very sick by the time they are diagnosed.

Signs and tests:

A urine analysis may be used to look for high blood sugar. However, a urine test alone does not diagnose diabetes.

Your health care provider may suspect that you have diabetes if your blood sugar level is higher than 200 mg/dL. To confirm the diagnosis, one or more of the following tests must be done.

Blood tests:

• Fasting blood glucose level -- diabetes is diagnosed if it is higher than 126 mg/dL twice. Levels between 100 and 126 mg/dL are called impaired fasting glucose or pre-diabetes. These levels are risk factors for type 2 diabetes.
• Hemoglobin A1c test --
  • Normal: Less than 5.7%
  • Pre-diabetes: 5.7% - 6.4%
  • Diabetes: 6.5% or higher
• Oral glucose tolerance test -- diabetes is diagnosed if glucose level is higher than 200 mg/dL after 2 hours. (This test is used more often for type 2 diabetes.)

Screening for type 2 diabetes in people who have no symptoms is recommended for:

• Overweight children who have other risk factors for diabetes, starting at age 10 and repeated every 2 years
• Overweight adults (BMI greater than 25) who have other risk factors
• Adults over age 45, repeated every 3 years