A mean corpuscular volume (MCV) test is a blood test that measures the size of your red blood cells. Our red blood cells carry oxygen around the body – if they are too large or too small, then it can be a sign of a blood disorder like anemia, or another medical condition.
An MCV test is normally done as part of a complete blood count (CBC), a group of tests that are routinely used to measure the number and different types of cells that are in your blood.
Why do I need a mean corpuscular volume (MCV) test?
Your doctor may request an MCV test as part of an overall health check-up. They may also request it if they think you have anemia or a long-term condition that may lead to anemia.
Anemia is a condition in which your blood doesn’t have enough red blood cells or not enough hemoglobin, the protein that carries oxygen. This leads to not enough oxygen in the blood, causing symptoms such as weakness, fatigue and shortness of breath.
An MCV test, alongside other tests, is used to diagnose anemia. There are different types of anemia, and each affects the size and shape of your red blood cells differently. The test can help doctors know which type of anemia you have.
What happens during the test?
An MCV test is just like any other blood test – a needle will be inserted into a vein, and a small amount of blood will be collected for testing.
It may sting a little but will be over in minutes.
What kind of results will I get after an MCV test?
Your doctor will receive your MCV test result as a number, which tells them the average size of your red blood cells and the range that is considered normal. The normal range for an MCV test is between 80 and 100 femtoliters (fL).
What do the MCV test results mean?
The MCV test result alone can’t diagnose a disease. The results will be looked at against other test results, as well as your medical history and symptoms, to confirm a diagnosis.
If your MCV test result shows that your red blood cells are larger than they should be, it could be a sign that you have:
- Pernicious anemia: A cause of vitamin B12 deficiency, this is an autoimmune disease that prevents you from absorbing vitamin B12.
- Vitamin B12 deficiency: When you aren’t getting enough vitamin B12 in your diet.
- Folate deficiency: When your blood doesn’t have enough vitamin B9 (folate).
- Liver disease.
If your MCV test result shows that your red blood cells are smaller than they should be, it could be a sign that you have:
- Iron deficiency anemia: Smaller than normal red blood cells can mean you an iron deficiency, a common type of anemia.
- Thalassemia: This is an inherited blood disorder which can cause the body to produce fewer healthy red blood cells and less hemoglobin.
- Other blood disorders that affect hemoglobin levels.
Sometimes, you can have anemia, but your MCV test result is normal. This tends to happen if you have anemia that is caused by sudden blood loss, kidney failure, or a rare type of anemia called aplastic anemia.
It is also possible to have an MCV test result that is not within the normal range and not have anemia or any other condition. Many factors, such as age, diet, medication, and menstruation can all affect MCV test results.
What else do I need to know about an MCV blood test?
A mean corpuscular volume (MCV) test will be requested by your doctor if they think you have anemia or another blood disorder. They will perform the test alongside other tests, like a red blood cell count, to confirm a diagnosis.
If you have any questions or concerns about your MCV test, always talk to your doctor.