A leukocyte count is a test that measures the number of white blood cells in your blood. This count is usually a part of a complete blood cell count test. Leukocyte means white blood cell.
White blood cells fight infection and red blood cells carry oxygen, aka erythrocytes. If your white blood cell count is low then this health condition is referred to as leukopenia. And a high leukocyte count is leukocytosis.
Your health care provider may order a leukocyte count to confirm an infection or a disease that affects white blood cells production. A white blood cell count may also be used to assess the success of treatment for certain health conditions.
The normal range for an overall white blood cell count varies amongst laboratories, but is generally between 4,300 and 10,800 cells per cubic millimeter of blood. Yet, the diagnostic value of leukocyte count doesn’t end here.
White blood cells are also tallied in a test called blood differential. This test measures the percentage of each type of white blood cell present in your blood. The five major types of white blood cells enumerated in a blood differential are:
White blood cell differential also indicates any abnormal or immature leukocytes.
“Normal” percentages for a white blood cell differential are:
- monocytes ~ 2% – 8%
- eosinophils ~ 1% – 4%
- basophils ~ 0.5% – 1%
- neutrophils ~ 40% – 60%
- lymphocytes ~ 20% – 40%
- band (young neutrophil) ~ 0% – 3%
A high count for one type of white blood cell can cause a low count for all the other type of leukocytes.
Some causes of a high neutrophil percentage in your differential leukocyte count are:
- acute stress
- acute infection
- rheumatic fever
- rheumatoid arthritis
- myelocytic leukemia
Some causes for a low neutrophil percentage in your differential leukocyte count are:
- aplastic anemia
- radiation therapy
- radiation exposure
- widespread bacterial infection
Some causes for a high lymphocytes percentage in your differential leukocyte count are:
- multiple myeloma
- infectious hepatitis
- bone marrow cancer
- lymphocytic leukemia
- chronic bacterial infection
- bacterial infection recovery
- viral infection ~ mononucleosis, mumps, measles
Some causes of a low lymphocytes percentage in your differential leukocyte count are:
Some causes of a high monocytes percentage in your differential leukocyte count are:
- parasitic infection
- chronic inflammatory disease
- virus infection ~ mononucleosis, mumps, measles
Some causes of a low monocytes percentage in your differential leukocyte count are:
Some causes for a high eosinophils percentage in your differential leukocyte count are:
Low count of eosinophils can be caused by an infection.
Basophils can increase because of:
Low count of basophils can be caused by an acute allergic reaction.
Certain drugs can interfere with white blood cell count test results. These drugs can cause a high or low affect on the count of your leukocytes:
- ACE inhibitors
- chemotherapy drugs
- allopurinol ~ treats gout
- quinine ~ treats malaria
- triamterene ~ treats edema
- laxatives containing psyllium
- amphetamines ~ appetite suppressants
- antithyroid drugs ~ treats hyperthyroidism
- barbiturates ~ treats anxiety, sleep disorders