Blood Health
MCV
What This Marker Tells Us
Measures the average size of your red blood cells, helping classify different types of anemia and revealing nutritional deficiencies or bone marrow disorders.
Why It Matters
MCV is essential for determining the cause of anemia because different conditions produce characteristically small, normal, or large red blood cells. Microcytic (small cell) anemia typically indicates iron deficiency, thalassemia, or chronic disease. Macrocytic (large cell) anemia suggests B12 or folate deficiency, alcohol excess, liver disease, or certain medications. Normocytic anemia points toward acute blood loss, kidney disease, or bone marrow problems. MCV also detects subtle nutritional deficiencies before anemia develops; B12 deficiency slowly enlarges cells, providing early warning. Even without anemia, abnormal MCV can reveal alcoholism (raises MCV), thalassemia trait (lowers MCV), or impending nutritional deficiencies.
How to Interpret Your Trends
Normal MCV is approximately 80-100 fL (femtoliters). MCV below 80 fL (microcytic) most commonly indicates iron deficiency, especially in women with heavy periods, but can also indicate thalassemia trait or chronic inflammation. MCV above 100 fL (macrocytic) suggests B12 or folate deficiency, particularly in vegans (B12 deficiency), alcoholics, or those with malabsorption. Mild macrocytosis (100-110 fL) may be seen with alcohol use or certain medications (metformin, methotrexate). Severe macrocytosis (above 115 fL) strongly suggests B12 or folate deficiency or myelodysplastic syndrome. Normal MCV with anemia (normocytic) points toward acute blood loss, kidney disease, or chronic disease.
What Influences This Marker
MCV decreases with iron deficiency (most common), thalassemia trait, chronic disease/inflammation, lead poisoning, and copper deficiency. MCV increases with B12 deficiency, folate deficiency, alcohol excess, liver disease, hypothyroidism, certain medications (methotrexate, antiretrovirals, chemotherapy), myelodysplastic syndrome, and aplastic anemia. Normal aging gradually increases MCV slightly. Pregnancy can cause mild macrocytosis. Combining microcytic and macrocytic causes (iron and B12 deficiency together) can produce misleadingly normal MCV.
How Your Team Uses It
Your coach implements dietary strategies providing iron (for microcytic anemia with low MCV), B12-rich animal foods or fortified options for vegetarians (for macrocytic anemia with high MCV), or folate-rich vegetables and legumes based on the underlying deficiency pattern.
Related Signals We Also Review
Hemoglobin, MCH, MCHC, RDW, ferritin, iron saturation, B12, folate, and reticulocyte count for complete anemia classification.