About HbA1c
HbA1c measures the percentage of hemoglobin that has glucose attached to it, reflecting your average blood sugar over the past 2–3 months. Unlike a single glucose reading, it can't be distorted by what you ate the day before — it's the gold-standard marker for diagnosing pre-diabetes (5.7–6.4%) and diabetes (6.5%+). The difference between a 'normal' and an 'optimal' HbA1c can mean years of protected metabolic function.