HbA1c
Glycated Hemoglobin
- Sample
- Blood
- Usual units
- %
- Fasting
- No fasting is usually needed.
Also known as Glycated Hemoglobin · Glycosylated Hemoglobin · Hemoglobin A1c · A1c · Glyco Hb
What this test measures
HbA1c is hemoglobin with glucose attached to it, formed as red blood cells circulate through blood carrying whatever glucose concentration is present. Because red blood cells last for months, the percentage of hemoglobin carrying glucose reflects glucose exposure averaged over that stretch of time rather than at a single moment. It is reported as a percentage.
Reading your report
There isn’t one standard range for this test — each lab prints its own. Use the range shown next to your result.
HbA1c unit converter
Convert HbA1c units
Labs print this test in % or mmol/mol depending on where the sample was run.
Related guides
- Guide
Why the same blood test has different "normal" ranges at different labs
Reference intervals are built from each lab's own population and equipment, which is why two labs can print different ranges for the same sample.
- Guide
Reference interval, cutoff, and the "optimal" numbers online: three different things
The range beside your result, the target a website quotes, and the threshold that defines a condition are built in different ways and answer different questions.
- Guide
Why the same lab printed a different reference range for you this year
Ranges are not fixed constants. The lab can change method, revise its reference group, or apply a range that depends on your age — none of which is an error.
- Guide
HbA1c and fasting glucose: a three-month average and a single moment
One is a snapshot of the morning you gave blood, the other reflects roughly three months. Why they can disagree, and what the estimated average glucose row is.
- Guide
What the H and L flags on a lab report actually assert
A flag compares your number to the range printed beside it on that page — nothing more. What it does not tell you, and why healthy people collect them.
- Guide
Panels, profiles and packages: what you actually paid for
A panel is a bundle of individual tests sold under one name, and the names are not standardised. How to work out what a package included — and what it left out.