Definition
A high white blood cell count is an increase in cells in the blood that fight infections.
What’s considered high in a white blood cell count varies from one lab to another. This is because laboratories set their own reference ranges based on the populations they serve. In general, for adults a count of more than 11,000 white blood cells in a microliter of blood is considered high.
Causes
A high white blood cell count usually means one of the following has increased the making of white blood cells:
An infection.
Reaction to a medicine.
A bone marrow disease
An immune system issue.
Sudden stress such as hard exercise.
Smoking.
Specific causes of a high white blood cell count include:
Allergy, especially severe allergic reactions
Asthma
Bacterial, viral, fungal or parasitic infections
Burns
Churg-Strauss syndrome
Medicines, such as corticosteroids and epinephrine
Hay fever (allergic rhinitis)
Leukemia
Lymphoma
Myelofibrosis (a bone marrow disorder)
Polycythemia vera
Pregnancy
Rheumatoid arthritis
Sarcoidosis
Smoking
Tuberculosis
Vasculitis
Whooping cough
