What can cause enlarged red blood cells?
Ask the doctor
Q. I just received my lab test results. Everything was normal except my red blood cells, which are enlarged. What can cause this?
A. Based on your question, you must have had a routine blood test that measures the number of red blood cells, white blood cells, and platelets. (This test is called a complete blood count or CBC.)
In addition, the test usually measures about 10 other values. These others provide important information when the amounts of red blood cells, white blood cells, or platelets fall out of the normal range. Most often, when all three numbers are normal, the other values will not reflect any health issues.
There are exceptions. I suspect that your report showed a high MCV. MCV stands for mean corpuscular volume. A high MCV would indicate that most of your red blood cells are larger than normal. The normal range for MCV is 80 to 100.
Causes of high MCV include:
- overuse of alcohol
- liver disease
- B vitamin deficiencies, specifically B12 or folic acid deficiency
- medication effects.
If your MCV has always been a little high (100 to 105) and all your other lab tests are in the normal range, a slightly high MCV is probably your normal.
A normal range of any test means that at least 95% of otherwise healthy people will have a test result in that range. Some people will always be a little above or a little below "normal."
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About the Author
Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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