MCV
Mean corpuscular volume (MCV) measures the average size of red blood cells in femtoliters (fL). It is the single most useful red cell index for classifying anemia: microcytic (smaller than usual), normocytic (usual size), or macrocytic (larger than usual). MCV is calculated from hematocrit divided by RBC count.
Why it matters: MCV immediately narrows the differential diagnosis of anemia. Low MCV strongly suggests iron deficiency or thalassemia. High MCV points to B12/folate deficiency, alcohol use, hypothyroidism, or medications. MCV is a PhenoAge biomarker — chronically abnormal MCV contributes to accelerated biological aging.
May increase with:
May decrease with:
What is MCV?
Mean corpuscular volume (MCV) measures the average size of red blood cells in femtoliters (fL). It is the single most useful red cell index for classifying anemia: microcytic (smaller than usual), normocytic (usual size), or macrocytic (larger than usual). MCV is calculated from hematocrit divided by RBC count.
What might a high or low MCV mean?
MCV immediately narrows the differential diagnosis of anemia. Low MCV strongly suggests iron deficiency or thalassemia. High MCV points to B12/folate deficiency, alcohol use, hypothyroidism, or medications. MCV is a PhenoAge biomarker — chronically abnormal MCV contributes to accelerated biological aging.
What is the typical reference range for MCV?
The general-population reference range shown here is 80 – 100 fL. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.
What can affect MCV?
It may be higher with: Vitamin B12 deficiency (impaired DNA synthesis), Folate deficiency, Chronic alcohol use (direct toxicity to RBC precursors), Hypothyroidism, Liver disease, Medications (methotrexate, phenytoin, azathioprine), Myelodysplastic syndrome, Reticulocytosis (young RBCs are larger). It may be lower with: Iron deficiency (most common cause), Thalassemia trait, Chronic disease (sometimes), Lead poisoning, Sideroblastic anemia, Copper deficiency.