What does a low white blood cell count mean?
Ask the doctor
Q. A test showed that I have a low white blood cell count of 3,800. I have not had any issues with my health besides a head cold. What are the most likely causes of a low white blood cell count?
A. White blood cell count is part of a blood test called complete blood count or CBC. Red blood cell and platelet counts are the other parts of a CBC.
The usual CBC lab report will show a normal range of 4,500 to 11,000 white blood cells. However, many healthy people have white blood cell counts that are lower than 4,500. At 3,800 white blood cells, you very likely have more than enough to fight infections.
When a person has a white blood cell count either below or above the normal range, I carefully look at the percentages of the different types of white blood cells reported as part of the CBC. The main ones are neutrophils, lymphocytes, and eosinophils. If the percentages of each are close to normal, then this is somewhat reassuring.
You mention that you had a head cold when the blood test was done. A common cause of a temporary low white blood cell count is a viral infection.
If this result is different from white cell counts you have had in the past, ask your doctor when the CBC should be repeated.
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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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