Anemia Biomarker
Collection Type: Blood
Related System: Anemia
Mean corpuscular volume (MCV) is the average volume of a red blood cell (RBC), reported in femtoliters (fL). It is calculated from the hematocrit and red cell count and is used to classify anemias as microcytic, normocytic, or macrocytic. Abnormal MCV suggests problems in hemoglobin synthesis, red cell production, or DNA synthesis. Common conditions suspected include iron‑deficiency anemia and thalassemia (low MCV), and vitamin B12/folate deficiency, alcohol use, or marrow disorders (high MCV). Symptoms that prompt testing include fatigue, pallor, shortness of breath, palpitations, jaundice or unexplained neurological signs. Normal MCV varies with age (newborns and infants have higher values) and may be slightly influenced by pregnancy and some laboratory reference differences between sexes.
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Q: What does it mean if MCV is low?
A: Low MCV indicates microcytosis red blood cells smaller than normal. It most commonly reflects iron‑deficiency anemia but can also occur with thalassemia traits, chronic inflammation, sideroblastic anemia or lead exposure. Symptoms include fatigue, pallor and shortness of breath. Evaluation usually involves a CBC with indices, iron studies, hemoglobin electrophoresis and clinical assessment; see a clinician for diagnosis.
Q: What does a high MCV mean?
A: A high MCV means red blood cells are larger than normal (macrocytosis). Common causes include vitamin B12 or folate deficiency, alcohol use, liver disease, hypothyroidism, certain medications, or bone marrow disorders. It may cause fatigue or be asymptomatic. Evaluation typically checks B12/folate, liver and thyroid tests, medication history and a blood smear. Treatment targets the underlying cause.
Q: Is it better to have high or low MCV?
A: It's better to have a normal MCV. Both high MCV (macrocytosis) and low MCV (microcytosis) suggest underlying problems—high can result from vitamin B12/folate deficiency, liver disease, alcohol use or certain drugs; low often indicates iron deficiency, thalassemia or chronic inflammation. Abnormal MCV needs medical evaluation and treatment aimed at the cause, not the number alone.
Q: What if MCH is low?
A: Low MCH means each red blood cell carries less hemoglobin than normal, often due to iron deficiency, thalassemia or chronic disease. It may cause fatigue, pallor and breathlessness. Evaluation includes CBC with MCV, iron studies and ferritin, and sometimes hemoglobin electrophoresis. Treatment targets the cause—iron supplements and diet for deficiency or disease‑specific care—so see your doctor for diagnosis and management.
Q: What should I eat if my MCV is high?
A: If your MCV is high, focus on vitamin B12 and folate-rich foods: lean red meat, fish, eggs, dairy and fortified cereals for B12; leafy greens, legumes, citrus, avocado and fortified grains for folate. Reduce alcohol and avoid unnecessary medications that affect B12 without medical advice. See your clinician for tests and targeted supplementation if deficiencies are confirmed.
Q: What makes MCV go down?
A: Low MCV (microcytosis) is most commonly caused by iron deficiency—due to poor intake, malabsorption, or chronic blood loss. Other causes include thalassemia and other hemoglobinopathies, anemia of chronic disease/inflammation, sideroblastic anemia, and lead poisoning. Rarely, certain medications or copper deficiency contribute. Evaluation usually includes iron studies, hemoglobin electrophoresis, and sometimes lead levels.