Hemoglobin A1c
Also known as: HbA1c, A1C, Glycated hemoglobin
Hemoglobin A1c reflects your average blood sugar over roughly the past two to three months. It measures how much sugar has attached to the hemoglobin in your red blood cells, giving a longer-term view than a single glucose reading.
Why it's measured
Because it captures a longer window, A1c is widely used to monitor blood sugar trends over time rather than at one moment. It is often checked during routine care and to follow blood sugar over the months between visits.
Typical range
Many labs report A1c as a percentage and flag values below about 5.7% as within the typical range, with higher bands labeled differently. The interpretation of your number depends on your personal history, which your doctor knows.
What high values can mean
A higher A1c reflects higher average blood sugar over recent months. It is a marker your doctor interprets in context, not a standalone diagnosis from a single report.
What low values can mean
Lower A1c values are common; unusually low results are occasionally noted alongside other findings and are worth a brief conversation with your doctor.
Questions to ask your doctor
- What does my A1c suggest about my blood sugar over the last few months?
- Should I have any additional testing to understand this better?
- How often would you like to recheck this?
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Try the explainerEducational information only — not medical advice, diagnosis, or treatment. Reference ranges vary by lab; always use your own lab's range and discuss results with a qualified clinician.