White Blood Cell Count

White Blood Cell Count (WBC’s):
Number of white blood cells – usually expressed as number in one cubic millimetre of whole blood.
Decrease (<4000/µl) = leuckopenia  drugs; SLE; rheumatoid arthritis; acute infection; vitamin B12 deficiency; congenital; bone marrow depression Increase (>10000/µl) = leucocytosis  infection; pregnancy; drugs; physical stress; burns

Differential is used to determine the relative amounts of WBC’s:

• Neutrophils (50-75%) – increase  bacterial infection. Left Shift = increase in immature neutrophils – nuclei not yet divided  acute bacterial infection; Right shift = liver disease, some types of anaemia
• Eosinophils (1-6%) – increase  allergic and parasitic conditions
• Basophils (1-2%)
• Monocytes (4-6%). Increase  viral infection; TB; collagen diseases; monocytic leukaemia; subacute bacterial endocarditis
• Lymphocytes (15-50%) increase  viral infection