White blood cell differential count
Differential leucocyte count; white blood cell morphology; WBC differential; Diff
To diagnose an illness affecting your immune system, such as an infection
As part of a full blood count (FBC), which may be requested for a variety of reasons
A blood sample drawn from a vein in your arm or by a finger-prick (children and adults) or heel-prick (infants)
There are five types of white blood cells, each with different functions: neutrophils, lymphocytes, monocytes, eosinophils and basophils. The differential reveals if these cells are present in normal proportions to one another, if one cell type is increased or decreased, or if immature or abnormal cells are present. This information is helpful in diagnosing a range of illnesses.
White blood cells are made in your bone marrow or lymphoid system. They protect your body against infection and aid your immune system. If an infection develops, white blood cells attack and destroy the bacteria or virus causing the infection.
The test is performed on a blood sample drawn from a vein in the arm or from a finger-prick (for children and adults) or heel-prick (for infants).
No test preparation is needed.
The white blood cell differential assesses the ability of the body to respond to and fight infection. It also detects the severity of allergic reactions, parasitic and other types of infection, and drug reactions. It can also identify some types of leukaemia or lymphoma.
The white blood cell differential is normally run as part of the full blood count (FBC), which is requested for many different conditions.
The results indicate the percentage and absolute number of each type of white blood cell that is present.
Eating, physical activity and stress may alter white blood cell differential values.
Long-term exposure to toxic chemicals (for example some solvents, petroleum products and insecticides) can increase the risk of an abnormal differential.
Full blood count, blood film
Tests: White blood cell count
Conditions: Bone marrow disorders, leukaemia
RCPA Manual: White cell count differential
Last Review Date: March 8, 2017