Mean Corpuscular Volume (MCV) Blood Test

The mean corpuscular volume (MCV) blood test, formerly known as the volume globulaire moyen blood test, measures the size of your red blood cells that carry oxygen from your lungs to cells throughout your body. The MCV test is used to diagnose blood conditions, such as anemia, hemoglobin disorders, vitamin deficiencies, liver disease, and thyroid problems.

What Is A Mean Corpuscular Volume (MCV) Blood Test?

The mean corpuscular volume (MCV) blood test, formerly known as the volume globulaire moyen (VGM) blood test, measures the size of your red blood cells that carry oxygen from your lungs to cells throughout your body. The test is performed as part of a routine complete blood count (CBC).

The size of your red blood cells can be a sign of certain health conditions, such as anemia, lead poison, vitamin deficiencies, liver disease, and thyroid problems.

Conditions we diagnose with an MCV blood test

• Anemia.
• Chronic inflammation.
• Hemoglobin disorder.
• Lead toxicity.
• Liver disease.
• Thyroid problems.
• Vitamin deficiencies.

Why Would I Need an MCV Test?

You may need an MCV test if you are having cognitive symptoms, such as forgetfulness, difficulty concentrating, dizziness, or fatigue.

Who’s a candidate for an MCV test?

You may be a candidate for an MCV test if your doctor wants to look for an underlying cause of neurological symptoms, iron deficiency, toxic exposure, or inflammation.

What Are the Risks and Complications of MCV Testing?

There are no risks associated with MCG testing. You may notice bruising and soreness in your arm after having your blood drawn. 

What Should I Expect From MCV Testing?

Before: How to prepare for MCV testing

MCG testing involves having your blood drawn. There is no special preparation required before the test.

How long does MCV testing take?

Obtaining a sample of your blood for MCV testing takes only a few minutes. Your blood will be sent to a lab for analysis, and your results should be available in a few days.

During your MCV test

During your MCV test, your provider will: 

• Ask you to sit in a chair.
• Clean your arm with an alcohol wipe.
• Tie an elastic band around your upper arm to make it easier to see your vein.
• Insert a needle into your vein to draw blood into a vial.
• Remove the needle after the vial is full.
• Put a bandage over the blood draw site.

Recovery after MCV testing

You should be able to resume your normal activities immediately after MCV testing. Your doctor will let you know when your test results are available and explain what they mean for you.

What do my MCV test results mean?

MCV test results can’t be used by themselves to diagnose any health conditions. However, they can be used in combination with other tests and your medical history to make a diagnosis.

Your MCV test results may be normal, or it may show:

• Normal-shaped red blood cells with a low red cell count — Called normocytic anemia, this result could be a sign of early-stage anemia, blood loss, or kidney/endocrine problems.
• Larger than normal red blood cells — Also known as macrocytic anemia, high MCV may be a sign of vitamin B12 or folate deficiency, liver disease, or alcoholism.
• Smaller than normal red blood cells — Also known as microcytic anemia, low MCV could be a sign of iron deficiency or thalassemia.

When to call your doctor about complications

Complications are rare after MCV testing. If you notice redness, drainage, or pus around your blood draw site, call your doctor.

By UPMC Editorial Staff. Last reviewed on 2026-05-20.