Pronunciation: aitch-bee-ay-one-see
Sometimes described as your “long-term blood sugar result”.
What it officially means
HbA1c (glycated haemoglobin) is a blood test that shows your average blood glucose level over the previous two to three months.
It works by measuring how much glucose has attached to haemoglobin, the protein in red blood cells that carries oxygen. Because red blood cells live for around 120 days, the test reflects longer-term trends rather than a single moment.
In the UK, HbA1c is usually reported in mmol/mol.
It is used to:-
- Diagnose diabetes
- Monitor diabetes
- Assess how well blood glucose is being managed
What people often hear
When you’re told your HbA1c result, it can feel like:-
- A score
- A pass or fail
- A judgement
- A verdict on your lifestyle
If you already test your blood sugar at home, it may not match your daily readings – which can be confusing.
You might also hear:-
- “It’s a bit high”
- “We’d like it lower”
- “That’s not too bad”
. . . without much context.
What it meant in practice
The hardest part to grasp is that HbA1c isn’t about yesterday. You can:-
- Eat well for a week
- Improve your steps
- Reduce alcohol
. . . and your HbA1c may barely move at first.
That’s because it reflects patterns over time, not short-term effort.
It also means:
- One bad weekend doesn’t “ruin” it
- One good week doesn’t fix it
For a reluctant patient, that can be both frustrating and oddly reassuring.
Why it matters
HbA1c is used as a key marker of diabetes risk and control.
Higher levels are associated with increased risk of:-
- Nerve damage
- Kidney problems
- Eye complications
- Cardiovascular disease
But the number is only one part of the picture. It doesn’t measure:-
- Stress
- Sleep
- Exercise habits
- How hard you’re trying
It measures biology over time – not effort.
Typical UK reference points (general guidance)
(Always follow clinical advice specific to you.)
- Below 42 mmol/mol: non-diabetic range
- 42–47 mmol/mol: pre-diabetes range
- 48 mmol/mol and above: diabetes range
Targets for people with diabetes are usually individualised.
Bottom line
HbA1c is a long-term blood sugar marker. It reflects patterns over months, not days – and it’s a trend indicator, not a moral judgement.