A White Blood Cell (WBC) count measures how many white blood cells are in your blood.
White blood cells are part of your immune system and help your body respond to infections, inflammation, and stress.
This test is usually part of a Complete Blood Count (CBC).
This test looks at the number of white blood cells circulating in your bloodstream.
White blood cells help:
Fight infections
Respond to inflammation
Support immune defense
Counts often change when your body is reacting to something.
Normal WBC ranges vary by lab and age.
Your lab report will show:
Your WBC count
The lab’s reference range
Being slightly above or below the range is very common.
High WBC counts are often caused by:
Infections
Inflammation
Stress or anxiety
Exercise
Certain medications
High counts usually come down on their own once the trigger resolves.
Low WBC counts may be linked to:
Viral infections
Medications
Temporary immune suppression
Vitamin deficiencies
Many people with mildly low WBC feel completely normal.
WBC counts can change due to:
Recent illness
Stress or poor sleep
Physical exertion
Lab timing
One result rarely tells the whole story.
Doctors may repeat this test if:
Levels are very high or very low
Symptoms are present
They want to monitor immune trends
Patterns over time matter more than one number.
Most changes in WBC count are temporary and reflect your body doing its job.
Doctors interpret WBC results together with symptoms and other labs.
A WBC count shows how active your immune system is.
Most abnormal results are not emergencies and often resolve without treatment.
You may want to read:
White Blood Cell Differential Explained
Complete Blood Count (CBC) Explained
Platelet Count Explained
You can also use the navigation bar above to explore other blood test results.
This information is for educational purposes only and is not medical advice. Always talk with a healthcare professional about your results.