Check a value against the reference
A single value is read alongside fasting glucose and your history.
- What it measures
- The proportion of haemoglobin that has glucose bound to it. Because red cells live about 120 days, it averages your glucose over that window rather than catching a single moment.
- Why it matters
- It is the single most useful number for spotting insulin resistance before it becomes diabetes, and it cannot be gamed by fasting the morning of the test.
- Typical adult reference
- Below 5.7% — normal · 5.7 to 6.4% — prediabetes · 6.5% or above — diabetes range
- When it is retested
- Twelve weeks. Testing sooner tells you little, since the average has not had time to move.