White blood cell differential count
Differential leucocyte count; white blood cell morphology; WBC differential; Diff
To help determine the cause of abnormal results on a White Blood Cell (WBC) count, to diagnose and/or monitor an illness affecting your immune system, such as an infection, inflammatory condition or cancer that affects your white blood cells
As part of a full blood count (FBC), which may be requested for a variety of reasons when results of a FBC fall outside the reference range, when you have a condition that affects WBCs like cancer or infection, when you are being treated with chemotherapy that is known to affect WBCs.
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. 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.
Some diseases trigger a response by the immune system that causes an increase in certain types of WBCs. The WBC differential gives clues to the specific cause of the immune response. For instance, it may help determine whether an infection is caused by a virus or by bacteria.
Other conditions affect the production of a particular type of WBC which results in either an increase or decrease in their number. Other tests may be performed following a WBC differential such as bone marrow biopsy, chromosome analysis or immunophenotyping to reveal the presence of abnormal and/or immature populations of WBCs.
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 examination
Tests: White blood cell count
Conditions: Bone marrow disorders, leukaemia
RCPA Manual: White cell count differential
Healthline - White blood cell count and differential
Last Review Date: September 30, 2020