Locations Main Campus: Chesterfield, MO 63017   |   Locations
314-434-1500 314-434-1500   |   Contact Us

Multimedia Encyclopedia


 
E-mail Form
Email Results

 
 
Print-Friendly
Bookmarks
bookmarks-menu

WBC count

Leukocyte count; White blood cell count

 

A WBC count is a blood test to measure the number of white blood cells (WBCs) in the blood.

WBCs help fight infections. They are also called leukocytes. There are five major types of white blood cells:

  • Basophils
  • Eosinophils
  • Lymphocytes (T cells, B cells, and Natural Killer cells)
  • Monocytes
  • Neutrophils

How the Test is Performed

 

A blood sample is needed.

 

How to Prepare for the Test

 

Most of the time, you do not need to take special steps before this test. Tell your health care provider the medicines you are taking, including the ones without a prescription. Some drugs may change the test results.

 

How the Test will Feel

 

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.

 

Why the Test is Performed

 

You will have this test to find out how many WBCs you have. Your body produces more WBCs for several reasons. The most common reasons are when you have an infection or allergic reaction. You can also have more WBCs when you are under stress or have inflammation. Some people naturally have a "normal" high or low number of WBCs. An increased number of WBCs can be due to a blood cancer, such as leukemia or lymphoma.

 

Normal Results

 

The normal number of WBCs in the blood is 4,500 to 11,000 white blood cells per microliter (mcL) or 4.5 to 11.0 x 10^9/L.

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

 

What Abnormal Results Mean

 

LOW WHITE BLOOD CELL (WBC) COUNT

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 fewer than 1700 neutrophils in a microliter of blood or 1.7 x 10^9/L has a low white blood cell count.
  • If there are fewer than 500 neutrophils in a microliter of blood or 0.50 x 10^9/L, 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 mononucleosis (mono)
  • Cancers that damage the bone marrow
  • Very severe bacterial infections

HIGH WHITE BLOOD CELL COUNT

A high number of WBCs is called leukocytosis. It may be due to:

  • Aplastic anemia
  • Certain drugs or medicines (see list below)
  • Cigarette smoking
  • Not having a spleen, due to spleen removal
  • 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 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

 

Risks

 

Veins and arteries vary in size from one patient to another, and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

  • Excessive bleeding
  • Fainting or feeling lightheaded
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)

 

 

References

Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 30.

 
  • Basophil (close-up)

    Basophil (close-up) - illustration

    Basophils are a specific type of white blood cell. These cells are readily stained with basic dyes (this is where the name comes from). Note the dark grains inside the cellular fluid (cytoplasm) of this basophil. Basophils make up only a small portion of the number of white blood cells but are important parts of the body's immune response. They release histamine and other chemicals that act on the blood vessels when the immune response is triggered.

    Basophil (close-up)

    illustration

  • Formed elements of blood

    Formed elements of blood - illustration

    Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.

    Formed elements of blood

    illustration

  • White blood cell count - series

    White blood cell count - series

    Presentation

    • Basophil (close-up)

      Basophil (close-up) - illustration

      Basophils are a specific type of white blood cell. These cells are readily stained with basic dyes (this is where the name comes from). Note the dark grains inside the cellular fluid (cytoplasm) of this basophil. Basophils make up only a small portion of the number of white blood cells but are important parts of the body's immune response. They release histamine and other chemicals that act on the blood vessels when the immune response is triggered.

      Basophil (close-up)

      illustration

    • Formed elements of blood

      Formed elements of blood - illustration

      Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.

      Formed elements of blood

      illustration

    • White blood cell count - series

      Presentation

    A Closer Look

     

      Self Care

       

        Tests for WBC count

         

         

        Review Date: 1/27/2015

        Reviewed By: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

        The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
        adam.com

         
         
         

         

         

        A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.



        Content is best viewed in IE9 or above, Firefox and Google Chrome browser.