White Blood Cell Count ( WBC )

Also known as : Leukocyte Differential Count ; Peripheral Differential ; WBC Count Differential ; Diff . 
Formal name : White Blood Cell Differential . 
Related tests : White Blood Cell Count , Complete Blood Count , Blood Smear , Bone Marrow Aspiration and Biopsy , Immunophenotyping , Chromosome Analysis . 

Why should I do it ?
To help determine the cause of abnormal results on a WBC count; to help diagnose and / or monitor an illness affecting your immune system , such as an infection or inflammatory condition , or cancers that affect your white blood cells , such as leukemia . 

When should I do it ?
As part of a complete blood count ( CBC ) , when you have a routine health examination ; when results of a CBC fall outside the reference range ; when you have any number of signs and symptoms that may be related to a condition affecting white blood cells , such as infection , inflammation , or cancer ; when you have a condition or are receiving treatment that is known to affect WBCs . 

What Kind of Sample is Needed ?
A blood sample drawn from a vein in your arm or by a fingerstick ( children and adults ) or heelstick ( infants ) . 

Test Preparation Needed ?
None .