Download WBC count also known as leukocyte count test

Kufa University
Medical College
Practical physiology
2nd yr
Dr.BAN DOSh
WBC count also known as leukocyte count test:The WBC count denotes the number of white blood cell per unit volume of
whole blood.
Methods :1. Manual method.
2. Electronic cell counting.
Manual white blood cell count
Materials & instruments
 Anticoagulated whole blood.
 Turk’s diluting fluid composed of
 Glacial acetic acid to haemolyse RBCs.
 Aqueous gention violet to color the nuclei of WBC.
 Distilled water.
 Wbc pipette, which is composedof a stem, mixing chamber, white
bead inside the mixing chamber, aspiration tube (ruber sucking
tube).
 Haemocytometer (Neubauer’s counting chamber) with cover slip.
 Microscope.
 Lancet.
 Cotton.
There are five major types of white blood cells:
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Basophils
Eosinophils
Lymphocytes (T cells and B cells)
Monocytes
Neutrophils
A low number of WBCs is called leukopenia. It may be due to:
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Bone marrow failure (for example, due to infection, tumor, or
abnormal scarring)
Collagen-vascular diseases (such as lupus erythematosus)
Disease of the liver or spleen
Radiation
A high number of WBCs is called leukocytosis. It may be due to:
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Anemia
Infectious diseases
Inflammatory disease (such as rheumatoid arthritis or allergy)
Leukemia
Severe emotional or physical stress
Tissue damage (for example, burn)
Normal count ranges from 4500-11000 WBC’s/c.mm
Leukemia:-is a group of malignant disordersof the haemopoietic tissue
associated with increase in the no.of primitive WBCs(blast cells)in the
bone marrow and there will be a failure of cell maturation and the
accumulation of useless cells which take up the bone marrow space and
eventually this proliferation spills into the blood.
Counts that continue to rise or fall to abnormal levels indicate that the
condition is getting worse.
Counts that return to normal indicate improvement.
Physiological factors that affected the number of WBC :1-Pregnancy in the final month and labor may be associated with
increased WBC levels.
2-spleenectomy may have a persistent mild to moderate increased WBC
count.
3-Diurnal variation the WBC count tends to be lower in the morning and
higher in the late afternoon .
4-Age affected the number of WBC count, on average, normal newborns
and infants have higher WBC count than adults.
5-Smoking may also cause an increased WBC count.
Indications to use this test:1-Conditions or medications that weaken the immune system such as HIV
infection, chemotherapy radiotherapy, cause a decrease in WBC count.
2-It used to determine the presence of an infection or leukemia.
3-It used also to help monitor the body‘s response to various treatments.
4-Also to monitor bone marrow function.
The volume of one corner square=1/10c.mm
Calculation:WBC count (per cubic mm)= N/volume x dilution factor
N =number of WBCs counted in 4 large squares.
Total volume over 4 large squares =1x1x1/10x4=4/10 cubic mm
Dilution factor=20
So wbc=N/4/10 X20= NX50