Understanding Elevated White Blood Cell Counts (Leukocytosis)

Elevated WBC count, medically known as leukocytosis, indicates an increase in disease-fighting white blood cells (leukocytes) circulating in the bloodstream which can occur for a number of reasons.

Significance

• A count of more than 10,500 leukocytes per microliter of blood is usually considered a high white blood cell count in adults.

Function

• An elevated white blood cell count usually indicates an infection in the body, a drug reaction, a bone marrow disease or an immune system disorder.

Specific Causes

• Some possible causes of an elevated white blood cell count include leukemia, allergic reaction, drugs (such as corticosteroids and epinephrine), measles, myelofibrosis, infection, smoking, rheumatoid arthritis, severe emotional or physical stress, tissue damage, tuberculosis and whooping cough.

Identification

• There are five major types of white blood cells, each with a different disease-fighting activity. Knowing which type is elevated helps to determine the underlying cause.

Considerations

• It is best to talk to your doctor if tests indicate a high white blood cell count. The specific type of cell that is elevated and results from other tests may indicate the underlying problem, or additional tests may be needed.