White Blood Cell Count (WBC) with Differential (Serum/Plasma Probe)
This test measures the types and proportions of white blood cells in your blood, helping identify infections, immune responses, or other conditions affecting your blood composition.
["Understanding your immune system’s response through cell types in your blood."]
Key facts at a glance
- LOINC
- 4523-7
- Short code
- iC3b Recep EntNum WBC
- Synonyms
- iC3b Recep EntNum WBC
- Category
- coagulation
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 4.5
- Ref high
- 11
- Critical range
- 2 N/A – 30 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85004
- SNOMED
- 900000000000003002
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test to diagnose or monitor conditions like infections (e.g., bacterial or viral), autoimmune diseases, blood disorders, or to check how your body is responding to treatment. It can also help evaluate symptoms such as fever, fatigue, or unexplained weight loss.
Types of White Blood Cells Measured
The differential counts individual white blood cell types, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Each type plays a role in fighting infections or regulating immune responses.
Sample Collection and Preparation
A small blood sample is drawn from your vein, typically in the arm. The blood is then analyzed to separate and count the different white blood cell types. The results help determine the proportions of each cell type present.
What the Results Mean
Abnormal counts of certain white blood cells can signal specific health issues. For example, high neutrophil counts may indicate infection, while high eosinophil counts could suggest allergies or parasitic infections. Your doctor will interpret these results in the context of your overall health and symptoms.
Reference range
Adult: 4.5-11.0 x 10^9/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
WBC Differential Profile
Frequently asked questions
What causes a change in my white blood cell counts?
How often should I get this test?
Can diet or lifestyle affect my white blood cell counts?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy