Metabolic
Hemoglobin A1c
LOINC 4548-4 · %
Ranges
Reference range: ≤ 5.6 %
What it is
Hemoglobin A1c reflects your average blood sugar over the past two to three months by measuring sugar attached to hemoglobin.
Why it matters
Because it averages glucose over months, it is a cornerstone for diagnosing and monitoring diabetes.
What high values can mean
A higher value indicates higher average blood sugar, in the prediabetes or diabetes range.
What low values can mean
A lower value reflects lower average blood sugar; very low results are interpreted in context.
How to improve it
The same habits that steady glucose — diet, activity, weight management and, when prescribed, medication — lower HbA1c over time.
Food & lifestyle
Whole foods, fibre, vegetables and limiting sugary drinks help; consistency over weeks moves this number.
Preparing for the test
No fasting is needed — HbA1c can be measured at any time of day.
When to talk to a doctor
Discuss a raised HbA1c with a doctor to confirm and plan next steps.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
See your own values in context
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