Community Answer

Answered by Dr. Emily Carter, MD

Doctors diagnose diabetes using several tests, including:

  • A1C Test: Measures average blood sugar levels over the past 2-3 months. Results are interpreted as follows:

    • Normal: Below 5.7%
    • Prediabetes: 5.7% to 6.4%
    • Diabetes: 6.5% or above
  • Fasting Plasma Glucose (FPG) Test: Measures blood sugar after an overnight fast. Results are interpreted as follows:

    • Normal: Less than 100 mg/dL
    • Prediabetes: 100 to 125 mg/dL
    • Diabetes: 126 mg/dL or higher
  • Oral Glucose Tolerance Test (OGTT): Measures blood sugar before and 2 hours after drinking a glucose-rich drink. Results are interpreted as follows:

    • Normal: Less than 140 mg/dL
    • Prediabetes: 140 to 199 mg/dL
    • Diabetes: 200 mg/dL or higher
  • Random Blood Sugar Test: Measures blood sugar at any time, regardless of when you last ate. A result of 200 mg/dL or higher suggests diabetes.

Doctors may use one or more of these tests to confirm a diagnosis. If you have symptoms of diabetes, such as frequent urination, excessive thirst, or unexplained weight loss, your doctor may recommend testing.

Last updated: 1/12/2025

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