Quick Guide: Mean corpuscular volume (MCV) Blood Test
What it is: Mean corpuscular volume (MCV) measures the average size of red blood cells, typically calculated as part of a complete blood count.
Why it's ordered: Ordered alongside a CBC to help classify the type and likely cause of anemia when hemoglobin or hematocrit are abnormal.
What it detects: MCV helps categorize anemia as microcytic (small cells, often iron deficiency or thalassemia), normocytic (normal-sized cells, often chronic disease or acute blood loss), or macrocytic (large cells, often vitamin B12/folate deficiency or liver disease).
Collection & prep: A standard blood draw from a vein in the arm, as part of a CBC. No special preparation is required.
Results:
Low (microcytic) – often points to iron deficiency or thalassemia
High (macrocytic) – often points to vitamin B12/folate deficiency, alcohol use, or liver disease
Normal (normocytic) – anemia, if present, is more likely due to chronic disease or recent blood loss
Possible complications: MCV narrows down the likely cause of anemia but doesn't diagnose it outright; abnormal results typically lead to targeted follow-up testing like iron studies or B12/folate levels.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
