HbA1cGlycated haemoglobin, A1cHbA1c measures the proportion of haemoglobin that has sugar stuck to it, which reflects the average blood glucose over roughly the past three months. It needs no fasting and is used both to diagnose diabetes and to judge how well it is controlled.
Reading your HbA1c result
HbA1c is the single number most used to judge diabetes control, and it is widely misread. This quiz covers the diagnostic and target ranges, how quickly it responds to change, and the conditions that make it unreliable.
7 questionsabout 4 minintermediateFree · no sign-up
Question 1/7
1. Which HbA1c value is in the diabetes range?
Every question, with the answer explained
The full set, for revision or for reading straight through. The correct answer is marked, and the explanation says why.
1. Which HbA1c value is in the diabetes range?
- Below 5.7% (39 mmol/mol)
- 5.7–6.4% (39–46 mmol/mol)
- 6.5% (48 mmol/mol) or above
- Any value after eating
6.5% (48 mmol/mol) or above. 6.5% or 48 mmol/mol and above is diagnostic. 5.7–6.4% is prediabetes, and below 5.7% is normal.
2. How long after a change in treatment is a repeat HbA1c useful?
- Two days
- One week
- About three months
- Two years
About three months. It reflects roughly three months of glucose, so retesting sooner mostly measures the old average. Three months is the standard interval.
3. Which condition can make HbA1c falsely low?
- Iron deficiency anaemia treated recently, or any condition shortening red cell life
- Drinking water
- Eating late
- Mild fever
Iron deficiency anaemia treated recently, or any condition shortening red cell life. Anything that shortens red-cell survival — haemolysis, recent blood loss, some anaemias — gives glucose less time to attach, and the result understates true control.
4. A common HbA1c target for many adults with type 2 diabetes is:
- Below 4%
- Around 7% (53 mmol/mol) or lower, individualised
- Exactly 9%
- There is no target
Around 7% (53 mmol/mol) or lower, individualised. About 7% suits many people, but the target is individual: looser for the frail or those prone to hypos, tighter for young people with long life expectancy.
5. Can you improve your HbA1c by fasting the day before the test?
- Yes, substantially
- No — it averages about three months
- Only if you fast 24 hours
- Only with medication
No — it averages about three months. This is the most common misunderstanding. Unlike a fasting glucose, HbA1c cannot be improved the night before, which is precisely why it is trusted.
6. What does a rising HbA1c on unchanged treatment usually mean?
- The lab made an error
- Diabetes is progressing, or diet, weight, activity or adherence has changed
- Nothing at all
- It always means insulin is needed
Diabetes is progressing, or diet, weight, activity or adherence has changed. Type 2 diabetes progresses over time, and treatment often needs stepping up. It is a signal to review, not a personal failure.
7. Does a good HbA1c rule out dangerous swings in blood sugar?
- Yes, completely
- No — an average can hide both highs and hypos
- Only in type 1
- Only if under 6%
No — an average can hide both highs and hypos. An average sits between the extremes. Someone swinging between hypos and high readings can post a reassuring HbA1c, which is why symptoms and home readings still matter.
Words used in this quiz
- HaemoglobinHemoglobin, HbHaemoglobin is the iron-containing protein inside red blood cells that binds oxygen in the lungs and releases it to the tissues. Its concentration in blood is the number used to diagnose anaemia.
- AnaemiaAnemia, Low haemoglobinAnaemia means the blood carries less haemoglobin than it should, so less oxygen reaches the tissues. It usually shows itself as tiredness, breathlessness on exertion and pallor, and in Pakistan the commonest cause by a wide margin is a shortage of iron.
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