White Blood Cell Count (with Differential Analysis)
This test measures the total number of white blood cells (WBCs) in your blood and breaks down their types (neutrophils, lymphocytes, monocytes, eosinophils, and basophils).
["It helps assess immune function and detect infections or inflammation."]
Key facts at a glance
- LOINC
- 32825-2
- Short code
- WBC Smn Ql
- Synonyms
- WBC Smn Ql
- Category
- chemistry
- 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
What Is a White Blood Cell Differential Test Used For?
A white blood cell differential test helps doctors identify the types and proportions of white blood cells in your blood. This can reveal clues about your immune system’s response to infections, inflammation, or other health conditions. For example, a high number of neutrophils might suggest a bacterial infection, while a high lymphocyte count could indicate a viral infection or chronic illness.
How Is This Test Performed?
Blood is drawn from a vein, typically in your arm. The sample is then analyzed under a microscope to count and identify the different types of white blood cells. Some labs may use automated machines to perform the differential count.
When Might You Need This Test?
You may need a white blood cell differential test if you have symptoms like frequent infections, unexplained fevers, fatigue, or signs of inflammation. It’s also used to monitor conditions like leukemia, autoimmune diseases, or after treatments like chemotherapy.
What Are Common Results and Their Meanings?
The differential provides percentages of each white blood cell type. For example, a high percentage of neutrophils could indicate acute infection, while a high percentage of lymphocytes might suggest chronic illness or immune response. Abnormal results don’t always mean a problem exists—your doctor will interpret them in the context of your symptoms and medical history.
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.
This test is critical for diagnosing and managing conditions affecting the immune system. For instance, an elevated total WBC count with a shift to immature cells may signal leukemia or severe infection. Conversely, a low WBC count could indicate bone marrow disorders or immune deficiencies. Doctors use these results to guide treatment, such as adjusting antibiotics or starting immunotherapy.
Short name
WBC Differential
Frequently asked questions
Why might my doctor order a white blood cell differential test?
What do my white blood cell differential results mean?
Can I prepare for this test?
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