A high level of white blood cells in the blood. A high white blood cell count can be caused by infection, reaction to a medicine, a bone marrow disease, an immune system issue, smoking or sudden stress such as hard exercise.
When to seek immediate medical care
See a health care professional immediately for the following symptoms:
- Persistent fever.
- High pulse rate.
- Night sweats.
When to make a doctor's appointment
Make an appointment to see a health care professional for:
- Increased fatigue.
- Recurrent infections.
