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MCV blood test

Mean corpuscular volume

In short

A typical adult MCV result is 78.2 to 97.9 fL. Larger-than-usual red cells are most often linked to alcohol, low vitamin B12 or folate, or some medicines. A small rise on its own is common and is often just watched. Always read your result against the range printed on your own report.

The average size of your red blood cells.

MCV measures the average size of the red blood cells. When hemoglobin is low, cell size is one of the best clues to the reason. MCV can also drift out of range before hemoglobin changes.

Is my MCV high or low?

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Typical range

ForRangeUnit
Adults78.2–97.9fL

Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.

If your MCV is high

Larger-than-usual red cells are most often linked to alcohol, low vitamin B12 or folate, or some medicines. A small rise on its own is common and is often just watched.

Common reasons

  • Regular alcohol use, even without liver problems
  • Low vitamin B12 or folate
  • Some medicines, including some seizure medicines and chemotherapy
  • An underactive thyroid
  • A liver condition
  • Many young red cells, after bleeding or when red cells break down early
  • Less often: a bone marrow condition, mostly in older adults

If your MCV is low

Smaller-than-usual red cells most often point to low iron. The next most common reason is thalassemia trait, a usually harmless inherited difference in hemoglobin.

Common reasons

  • Low iron, often from heavy periods, pregnancy or blood loss
  • Thalassemia trait, a usually harmless inherited difference in hemoglobin
  • Long-term inflammation or illness, such as arthritis or kidney disease
  • Less often: slow, hidden bleeding from the stomach or bowel
  • Less often: lead exposure or a rare inherited anemia

What can throw it off

A sample left standing for hours before testing, or very high blood sugar, can make MCV read a little high.

Questions to take to your appointment

  1. 1Should my iron stores (ferritin) be checked?
  2. 2Could this be an inherited trait rather than low iron?
  3. 3Do my other red cell results point the same way?

Read together with

Doctors rarely read MCV alone. These usually sit next to it.

Quick answers

What is the MCV blood test?

MCV (Mean corpuscular volume): The average size of your red blood cells. MCV measures the average size of the red blood cells. When hemoglobin is low, cell size is one of the best clues to the reason. MCV can also drift out of range before hemoglobin changes.

What is a normal MCV level?

For most adults, MCV is typically 78.2 to 97.9 fL. Labs differ a little, so the range printed next to your result is the one to go by.

What does a high MCV mean?

Larger-than-usual red cells are most often linked to alcohol, low vitamin B12 or folate, or some medicines. A small rise on its own is common and is often just watched. Common reasons include regular alcohol use, even without liver problems; low vitamin B12 or folate; some medicines, including some seizure medicines and chemotherapy; and an underactive thyroid. A doctor reads it together with your other results and how you feel.

What does a low MCV mean?

Smaller-than-usual red cells most often point to low iron. The next most common reason is thalassemia trait, a usually harmless inherited difference in hemoglobin. Common reasons include low iron, often from heavy periods, pregnancy or blood loss; thalassemia trait, a usually harmless inherited difference in hemoglobin; long-term inflammation or illness, such as arthritis or kidney disease; and less often: slow, hidden bleeding from the stomach or bowel.

What can affect my MCV result?

A sample left standing for hours before testing, or very high blood sugar, can make MCV read a little high.

What should I ask my doctor about my MCV?

Questions worth taking to the appointment: Should my iron stores (ferritin) be checked? Could this be an inherited trait rather than low iron? Do my other red cell results point the same way?

What this page can’t do

It reads each number on its own.

Doctors read results together — ALT with AST, ferritin with hemoglobin, TSH with free T4. A pattern says more than any single flag.

It doesn't know you.

Your age, your medicines, how you feel and your last result all change what a number means.

It doesn't remember.

Close this page and your results are gone. That's on purpose: nothing was ever sent to us.

We also make Vita: Health Coach, an app for those parts. It reads your whole report with your medicines and history in mind, answers follow-up questions in plain words, and keeps your reports in one place — for you and for the people you look after.

Vita: Health Coach on the App Store

Sources

Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.