What Is an HbA1c Blood Test?

HbA1c measures the percentage of hemoglobin with glucose attached, reflecting 3-month average glucose.

Ranges

• Normal: below 5.7%
• Prediabetes: 5.7–6.4%
• Diabetes: 6.5%+
• Goal for diabetics: below 7.0%

Why Gold Standard

• No fasting required
• Not affected by recent meals
• Correlates with complication risk

Limitations

• Anemia affects results
• Hemoglobinopathies
• Pregnancy
• Kidney disease

Testing Frequency

• Screening: every 3 years from 35
• Prediabetes: annually
• Diabetes stable: every 6 months
• Uncontrolled: every 3 months