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White Blood Cell Count

The normal number of white blood cells (WBCs) in the blood is 4,500-10,000 white blood cells per microliter (mcL).

Normal value ranges may vary slightly among different labs. Some laboratories use different measurements or may test different specimens. Talk to your doctor about your test results.

The examples above show the common measurements for results for these tests.


A low number of WBCs is called leukopenia. A WBC count below 4500 is below normal

One type of white blood cell is the neutrophil. This type of white blood cell is important for fighting infections.

  • An adult with who has fewer than 1700 neutrophils in a microliter of blood has a low white blood cell count.
  • If there are fewer than 500 neutrophils in a microliter of blood, the risk for infection becomes even higher.

It may be due to:

  • Bone marrow deficiency or failure (for example, due to infection, tumor, or abnormal scarring)
  • Cancer treating drugs, or other medicines (see list below)
  • Certain autoimmune disorders such as lupus
  • Disease of the liver or spleen
  • Radiation treatment for cancer
  • Certain viral illnesses, such as Mono
  • Cancers that damage the bone marrow
  • Very severe bacterial infections

High WBC Count

  • A high number of WBCs is called leukocytosis. It may be due to:
  • Anemia
  • Certain drugs or medications (see list below
  • Cigarette smoking
  • Infections, most often those caused by bacteria
  • Inflammatory disease (such as rheumatoid arthritis or allergy)
  • Leukemia
  • Severe mental or physical stress
  • Tissue damage (for example, burns)

There may also be other less common reasons for this result. .

Drugs that may lower your WBC count include:

  • Antibiotics
  • Anticonvulsants
  • Anti thyroid drugs
  • Arsenicals
  • Captopril
  • Chemotherapy drugs
  • Chlorpromazine
  • Clozapine
  • Diuretics
  • Histamine-2 blockers
  • Sulfonamides
  • Quinidine
  • Terbinafine
  • Ticlopidine

Drugs that may increase WBC counts include:

    • Beta adrenergic agonists (for example albuterol)
    • Corticosteroids
    • Epinephrine
    • Granulocyte colony stimulating factor
    • Heparin
    • Lithium


People who have had their spleen removed will always have a slightly higher number of WBCs.