White Blood Cell
Differential Count
Also known as: Leukocyte differential count; Peripheral differential; White blood cell morphology; WBC differential; Diff
Formal name: White Blood Cell Count Differential
Related tests: Complete blood count; Blood smear
At a Glance
Why Get Tested?
To diagnose an illness affecting your immune system, such as an infection or viral condition, or other diseases that affect your white blood cells, such as leukemias
When to Get Tested?
As part of a complete blood count (CBC), which may be ordered for a variety of reasons
Sample Required?
A blood sample drawn from a vein in your arm or by a fingerstick (children and adults) or heelstick (infants)
Test Preparation Needed?
None
