What is MCV?
the size of your red cells
MCV is the average size of your red cells. When anaemia is present, MCV helps identify the cause - iron deficiency makes cells smaller, B12 or folate deficiency makes them larger.
MCV is the first step in classifying anaemia as microcytic (small cells), normocytic, or macrocytic (large cells). The classification guides which follow-up tests are needed.
Test facts
- Unit
- fL
- Sample
- Whole blood
- Fasting
- No fasting needed
- Turnaround
- 1 day
What does low MCV mean?
Low MCV (microcytosis) typically reflects iron deficiency, but can also indicate thalassaemia or chronic inflammation.
What does high MCV mean?
High MCV (macrocytosis) appears with B12 or folate deficiency, heavy alcohol use, certain medications, and thyroid disease.
Panels that measure MCV
- Essentials
- Deep Baseline
- Female Annual
- Male Annual
More markers in the same area
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This is general information about the marker, not an assessment of your values and not medical advice. Last updated: May 2026.