what blood tests show diabetes

Several blood tests can diagnose diabetes or prediabetes. The most common ones include:

• A1C Test: Measures your average blood sugar levels over the past 2-3 months. Results are given as a percentage:

  • 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.

  • Normal: Less than 100 mg/dL
  • Prediabetes: 100-125 mg/dL
  • Diabetes: 126 mg/dL or higher

• Oral Glucose Tolerance Test (OGTT): Measures blood sugar before and 2 hours after drinking a sugary drink.

  • Normal: Less than 140 mg/dL
  • Prediabetes: 140-199 mg/dL
  • Diabetes: 200 mg/dL or higher

• Random Blood Sugar Test: Measures blood sugar at any time, regardless of when you last ate.

  • Diabetes: 200 mg/dL or higher (with symptoms like increased thirst or frequent urination)

Your healthcare provider may use one or more of these tests to confirm a diagnosis.