White Blood Cell Count (WBC) with Differential Analysis
This test measures the types and proportions of white blood cells in your blood, helping identify infections, inflammation, or other conditions affecting your immune system.
["Assessing immune health and potential infections through blood cell types."]
Key facts at a glance
- LOINC
- 5419-7
- Short code
- Deprecated CD104 WBC-aCnc
- Synonyms
- Deprecated CD104 WBC-aCnc
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- 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
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
White blood cells (WBCs) are crucial for fighting infections and inflammation. A differential analysis breaks down these cells into categories like neutrophils, lymphocytes, eosinophils, basophils, and monocytes. This helps doctors diagnose conditions like infections, allergies, autoimmune diseases, or blood disorders.
How the Test Works
Blood is drawn from a vein, typically in your arm. The sample is then examined under a microscope to count and identify each type of white blood cell. Advanced labs may use automated machines for precise measurements.
Common Reasons for Testing
Doctors may order this test if you have symptoms like fever, fatigue, frequent infections, unexplained weight loss, or signs of inflammation. It’s also used to monitor conditions like leukemia, lymphoma, or chronic infections.
What to Expect Before the Test
No special preparation is usually needed, but inform your doctor about any medications, recent illnesses, or conditions that might affect results (e.g., infections, steroids). Avoid strenuous activity 24 hours before the test.
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
Frequently asked questions
An elevated WBC count may indicate infection, inflammation, or stress, while a low count could signal immune deficiencies or bone marrow disorders. Abnormal differentials (e.g., high eosinophils) may point to allergies, parasites, or autoimmune diseases. Regular monitoring helps track treatment effectiveness for chronic conditions.
A high WBC count often signals an active infection, immune response, or inflammation. A low count may suggest immune system weakness, bone marrow problems, or certain medications. Your doctor will interpret results in the context of your symptoms and medical history.
Dietary changes or intense exercise can temporarily influence white blood cell levels, but they usually return to normal within a few days. Avoid extreme stress or high-intensity workouts before testing to minimize variability.
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