White Blood Cell Count

(The white blood cell count is also known as WBC.)

A count is done of the actual number of white cells in a specific volume of blood.

The white blood cells are the cells of our immune system that fight infection. There are a number of different types of white blood cells and that is the reason that the 'differential' tests, which are described later, are done.

Normal values are
4.0 - 11.0 x 10*9 cells/L. - expressed in SI units.
4,000 and 11,000 cells/ cu.mm (cubic millimetres) or /µl (per microlitre of blood) - US units.

Significance of abnormal results

Increased WBC count - called leukocytosis:-
Bacterial infection somewhere in the body, more tests need to be done to find the cause if it is not obvious. Diabetics with high blood sugars are prone to infections and may well have elevated WBC counts.
Inflammation as in rheumatoid arthritis or allergy
Leukaemia - cancer of the white blood cells.
Chronic bone marrow diseases such as a myeloproliferative disorder
Trauma with severe tissue damage, as in bad burns.
Extreme physical or emotional stress can raise the WBC count.
WBC count may be elevated in the late stages of pregnancy.
A splenectomy results in a permanent mild rise in WBC count.
Medications eg.
Epinephrine - also called adrenaline. Used to relieve asthma.
Allopurinol (Zyloprim) - used to lower blood uric acid levels, eg gout & kidney stones.
Heparin - anticoagulant
Quinine - used to treat malaria and also leg cramps.
Corticosteroids -
Triamterene (Dyrenium) - a diuretic.

Decreased WBC count - called leukopenia:-
Thyroid dysfunction.
Vitamin deficiencies.
Diseases of the liver or spleen.
Bone marrow failure (possibly due to infection, tumour or fibrosis)
A severe infection such as occurs in viral diseases, tuberculosis & typhoid.
An autoimmune disease such as HIV or Lupus.
Cancer, chemotherapy and radiation therapy can affect bone marrow production of white blood cells.
Congenital disease called Marrow Aplasia, where the marrow doesn't develop normally.
Any exposure to radiation (such as occurred in accidents like Chernobyl).
Some medications eg.
Methotrexate - blocks the metabolism of cells. Used in psoriasis, breast cancer and rheumatoid arthritis.
Antithyroid drugs
Chemotherapeutic agents

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