BiomarkersMCV
Blood & iron
MCV
The average size of your red blood cells
On your report it may say: Mean corpuscular volume
MCV measures how big your red blood cells are on average. Small cells often point to low iron or thalassaemia trait; large cells can point to low B12 or folate, alcohol or thyroid issues.
Typical ranges · fL
Mixed deficiencies (iron plus B12) can produce a normal MCV, so it's only a clue.
Ranges vary by lab, age and sex. The range printed on your report applies.
If it's low
Your red cells are smaller than usual (microcytic).
Common causes
- Iron deficiency
- Thalassaemia trait (common in India)
- Chronic illness
What you might notice
- Same as anaemia
If it's high
Your red cells are larger than usual (macrocytic).
Common causes
- Low B12 or folate
- Alcohol
- Underactive thyroid
- Some medicines
What you might notice
- Same as anaemia
- tingling if B12 is low
Testing
- Who should test
- Reported automatically with every CBC.
- How to prepare
- No fasting needed.
- When to retest
- With your CBC.
What can help
See a doctor to find the cause of small or large cells before taking supplements.
Common questions
Why does thalassaemia trait matter?
It causes small cells without low iron, so iron won't help and can harm.
Can MCV be normal with anaemia?
Yes, when two causes cancel out.
Explore further
Sources
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Build My Nutrition PlanFor general education only, not medical advice. Ranges shown are typical for adults; the range printed on your lab report applies. Talk to a qualified doctor about your results.