Mean Corpuscular Volume
Also written as: MCV, Red cell size
The average size of your red blood cells.
What it measures
The average volume of a single red blood cell. It tells a clinician whether red cells are unusually small, unusually large, or typical in size.
Why a doctor orders it
It is reported automatically with every CBC and is one of the most useful values for narrowing down the cause of an anemia, because different causes produce different cell sizes.
What is generally associated with a higher result
Larger-than-typical red cells are broadly associated with vitamin B12 or folate deficiency, alcohol use, certain medications, thyroid underactivity, and some bone marrow conditions.
What is generally associated with a lower result
Smaller-than-typical red cells are broadly associated with iron deficiency and with inherited hemoglobin conditions such as the thalassemias.
Everyday things that move this number
Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:
- Alcohol intake
- Several common medications
- Coexisting deficiencies, which can offset each other and produce a middling value
Questions to take to your appointment
- Does this point toward a particular cause of anemia?
- Should B12, folate, or iron studies be checked alongside this?
Build a printable questionnaire with your own results →
Where to read more
MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .
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