HbA1c (glycated haemoglobin) measures the percentage of haemoglobin bound to glucose. Since red blood cells live ~120 days, HbA1c reflects average blood sugar over the past 8–12 weeks.
Interpretation: Normal <5.7%; Prediabetes 5.7–6.4%; Diabetes ≥6.5%. DM target: <7%.
Advantages over fasting glucose: no fasting required, one blood draw, results not affected by what you ate hours before, more stable.
When to test: every 3 months for active DM; every 6 months for well-controlled DM; yearly for screening if age ≥35 with risk factors.
HbA1c is included in Prime Lab’s Diabetes Screening package.