1. Hemoglobin A1C
The A1C test measures average blood sugar over the past 2–3 months. • Normal: below 5.7% • Prediabetes: 5.7–6.4% • Diabetes: 6.5% or higher
2. Fasting Plasma Glucose (FPG)
After an 8-hour fast: • Normal: below 100 mg/dL • Prediabetes: 100–125 mg/dL • Diabetes: 126 mg/dL or higher
3. Oral Glucose Tolerance Test (OGTT)
Checks blood sugar 2 hours after drinking a glucose drink: • Normal: below 140 mg/dL • Prediabetes: 140–199 mg/dL • Diabetes: 200 mg/dL or higher
When & Why
Your doctor may order these tests if you have risk factors such as obesity, family history, or symptoms like excessive thirst, unexplained weight loss, or fatigue.