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Medical Tests
5 min readReviewed Sep 2026The A1C Test, Explained in Plain Language
Quick Answer (TL;DR)
A1C estimates your average blood sugar over roughly the last three months, reported as a percentage.
What It Means
Unlike a single glucose reading, A1C reflects how much sugar has attached to your red blood cells over their lifespan. Below 5.7% is generally normal, 5.7 to 6.4% suggests prediabetes, and 6.5% or higher on two tests supports a diabetes diagnosis.
Why It Matters for Your Health
A1C is used both to diagnose diabetes and to track how well a treatment plan is working, without needing you to fast.
Recommended Biomarker or Metric to Track
Keep every A1C result with its date so you can see the direction of travel.
Questions to Ask Your Doctor
Targeted questions based on latest clinical consensus statements.
1What is my A1C, and how has it changed?
2Does anything in my history make A1C less reliable for me?
3What target are we aiming for?
4What would move this number most in three months?
5When should we repeat the test?
CDC - All About Your A1C
American Diabetes Association - Understanding A1C
NHS - HbA1c test
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