Blood WorkMCV (mean corpuscular volume) is the average size of your red blood cells. It's part of a complete blood count (CBC), and the typical range is about 80 to 100 fL. Low MCV (small cells) most often means iron deficiency or thalassemia trait; high MCV (large cells) often comes from alcohol, certain medicines, low vitamin B12 or folate, liver disease or an underactive thyroid.
What does MCV measure?
MCV is the average volume of a single red blood cell, measured in femtoliters (fL). It's one of the most useful numbers on a blood count because it sorts anemia into three kinds: small-cell (microcytic), normal-size (normocytic) and large-cell (macrocytic). Each kind has a different short list of causes.
What is a normal MCV?
| Result | What it usually means |
|---|---|
| Below 80 fL | Small red cells (microcytosis): iron deficiency, thalassemia trait, chronic inflammation. |
| 80 to 100 fL | Typical adult range. |
| Above 100 fL | Large red cells (macrocytosis): B12 or folate deficiency, alcohol, liver disease, thyroid, medicines. |
Your lab's printed range applies. MCV can be normal early in iron deficiency, and two problems at once (for example low iron and low B12) can cancel each other out; RDW helps spot that.
What does low MCV mean?
- Iron deficiency, the most common cause. A ferritin test confirms it.
- Thalassemia trait, an inherited condition with small cells, often a near-normal hemoglobin and a high red cell count.
- Anemia of chronic disease, from long-term inflammation, infection or kidney disease.
- Rarer causes: lead poisoning and sideroblastic anemia.
In men and in women after menopause, iron deficiency usually needs a check of the stomach and colon for slow bleeding (American Gastroenterological Association).
Call 911 or go to the ER if a low result comes with chest pain, fainting or severe shortness of breath. Get care the same day for black or bloody stools.
What does high MCV mean?
- Low vitamin B12 or folate. Metformin and long-term acid reducers can lower B12; low folate is uncommon in the US because foods are fortified. See the vitamin deficiency guide.
- Regular alcohol use, even without liver disease.
- Liver disease and an underactive thyroid.
- Medicines such as methotrexate, hydroxyurea, some seizure and HIV medicines.
- A burst of new red cells after bleeding or red cell breakdown, since young cells are larger.
- Bone marrow conditions, such as myelodysplastic syndrome, especially in older adults with other abnormal counts.
If your MCV is off at Passion Health
A Texas-licensed clinician reviews every result and calls you the same day about anything critical. One result outside the range is common and often harmless; we read it with the rest of your panel, your history and your medicines, and recheck when that's the sensible next step.
For low MCV we check ferritin and iron studies; if iron is normal, thalassemia trait is the next question. For high MCV we check B12, folate, thyroid and liver tests and review alcohol and medicines. The Energy & Iron Panel ($119) covers most of these in one draw.
MCV test cost in Texas
Self-pay. MCV comes with every complete blood count. In Essential Blood Work ($59) it's part of 33 results with the draw and a clinician's review included; on its own, the complete blood count is $20 plus the $29 draw and review fee ($49).
With insurance. If we're in network with your plan, we bill it when the test is covered. You pay cash for a test only after we tell you the price in writing, and Medicare patients sign an Advance Beneficiary Notice first.
MCV blood test questions
What is MCV in a blood test?
MCV, mean corpuscular volume, is the average size of your red blood cells. It's part of a complete blood count, and the typical range is about 80 to 100 fL.
What does a high MCV mean?
Large red cells, most often from regular alcohol use, certain medicines or low vitamin B12 (metformin and long-term acid reducers can lower B12). Liver disease and an underactive thyroid are other causes; low folate is uncommon in the US because foods are fortified. B12, folate, thyroid and liver tests are the usual next steps.
What does a low MCV mean?
Small red cells, most often from iron deficiency or thalassemia trait. A ferritin test tells them apart: low ferritin means iron deficiency.
Can MCV be high without anemia?
Yes. MCV can rise before hemoglobin falls, and alcohol, some medicines and thyroid problems raise MCV without causing anemia. It's still worth a look at B12, folate and alcohol intake.
Do I need to fast for an MCV test?
No. A blood count doesn't need fasting. If it's drawn with a metabolic panel or cholesterol, as in Essential Blood Work, fast 8 to 12 hours for those.