Blood health
Mean corpuscular volume (MCV)
Included in every MyHealthspan membership: Focus, Baseline, and Complete.
Compare membershipsRed cell size, one of the first clues.
MCV measures the average size of your red blood cells. When hemoglobin is low, MCV is one of the first clues clinicians use to narrow down why.
Small, normal, or large cells point in different directions.
Smaller-than-usual red cells most often point toward iron deficiency or an inherited hemoglobin difference such as thalassemia trait. Larger-than-usual cells can point toward low vitamin B12 or folate, regular alcohol use, liver disease, or certain medications.
MCV can sit outside the reference range even when hemoglobin is normal, so it's worth reading on its own as well as alongside your other red cell results.
MCV answers a simple question: are your red cells small, normal, or large?
Questions
Can MCV be high without a vitamin problem?
Yes. Regular alcohol use, liver disease, some medications (including certain chemotherapy drugs), and a surge of young red cells after blood loss can all raise MCV. Your B12, folate, and liver results help a clinician tell these apart.
Is a normal MCV always reassuring?
Usually it is, with one well-known exception. If two causes overlap, such as low iron (smaller cells) and low B12 (larger cells), the average can land in the normal range. RDW, which measures how much cell sizes vary, can help reveal that mix.