WBC blood test
White blood cell count
In short
A typical adult WBC result is 3.4 to 9.6 x10^3/µL. A mildly high count is common and most often comes from an infection, stress or smoking. Which type of white cell is raised helps show the reason. Always read your result against the range printed on your own report.
The total number of white blood cells, the body's infection fighters.
White blood cells fight infection and help the body heal. This number adds up all five types, so doctors read it together with the count of each type. It moves with everyday things like a cold, stress or smoking.
Is my WBC high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Adults | 3.4–9.6 | x10^3/µL |
Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.
If your WBC is high
A mildly high count is common and most often comes from an infection, stress or smoking. Which type of white cell is raised helps show the reason.
Common reasons
- A current or recent infection, most often bacterial
- Smoking, which keeps the count a little higher
- Physical or emotional stress, hard exercise or recent surgery
- Steroid medicines, which can raise the count
- Pregnancy, when a higher count is expected
- Ongoing inflammation, such as from arthritis or a bowel condition
- Less often: a bone marrow condition, such as leukemia
If your WBC is low
A slightly low count is common and often harmless, especially after a viral illness. What matters most is how low it is and whether neutrophils, the main bacteria fighters, are low too.
Common reasons
- A recent viral illness, such as a cold or flu
- A naturally lower count, common in people of African or Middle Eastern ancestry
- Some antibiotics, some seizure medicines or medicines for an overactive thyroid
- Low vitamin B12 or folate
- An autoimmune condition, such as lupus
- Chemotherapy or radiation treatment
- Less often: a bone marrow condition
What can throw it off
A recent infection, hard exercise, stress, smoking and steroid medicines can all raise the count for a while.
When it can’t wait
A WBC of 100 x10^3/µL or more usually needs a doctor's attention the same day. Call your doctor’s office, or their after-hours line. If you feel very unwell, call your local emergency number.
Questions to take to your appointment
- 1Which type of white cell is out of range?
- 2Could a recent illness or my medicines explain it?
- 3Should we repeat the count in a few weeks?
Read together with
Doctors rarely read WBC alone. These usually sit next to it.
- NeutrophilsThe most common white blood cells, the first to fight bacteria.
- LymphocytesWhite blood cells that fight viruses and make antibodies.
- MonocytesWhite blood cells that clean up germs and damaged tissue.
- EosinophilsWhite blood cells involved in allergies and fighting parasites.
- CRPA protein the liver makes when there is inflammation.
Quick answers
What is the WBC blood test?
WBC (White blood cell count): The total number of white blood cells, the body's infection fighters. White blood cells fight infection and help the body heal. This number adds up all five types, so doctors read it together with the count of each type. It moves with everyday things like a cold, stress or smoking.
What is a normal WBC level?
For most adults, WBC is typically 3.4 to 9.6 x10^3/µL. Labs differ a little, so the range printed next to your result is the one to go by.
What does a high WBC mean?
A mildly high count is common and most often comes from an infection, stress or smoking. Which type of white cell is raised helps show the reason. Common reasons include a current or recent infection, most often bacterial; smoking, which keeps the count a little higher; physical or emotional stress, hard exercise or recent surgery; and steroid medicines, which can raise the count. A doctor reads it together with your other results and how you feel.
What does a low WBC mean?
A slightly low count is common and often harmless, especially after a viral illness. What matters most is how low it is and whether neutrophils, the main bacteria fighters, are low too. Common reasons include a recent viral illness, such as a cold or flu; a naturally lower count, common in people of African or Middle Eastern ancestry; some antibiotics, some seizure medicines or medicines for an overactive thyroid; and low vitamin B12 or folate.
What can affect my WBC result?
A recent infection, hard exercise, stress, smoking and steroid medicines can all raise the count for a while.
When is my WBC result urgent?
A WBC result of 100 x10^3/µL or more usually needs a doctor's attention the same day. Call your doctor's office or their after-hours line. If you feel very unwell, call your local emergency number.
What should I ask my doctor about my WBC?
Questions worth taking to the appointment: Which type of white cell is out of range? Could a recent illness or my medicines explain it? Should we repeat the count in a few weeks?
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 StoreSources
- Mayo Clinic Laboratories — CBC with differential, reference values
- Mayo Clinic Laboratories — Critical values list
- MedlinePlus — Complete blood count (CBC)
Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.