Complete Blood Count with Automated Differential (WBC Differential)
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.
["Understanding your white blood cell types can help doctors diagnose and treat health issues."]
Key facts at a glance
- LOINC
- 6690-2
- Short code
- WBC # Bld Auto
- Synonyms
- WBC # Bld Auto
- 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
- Method
- automated-count
- 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 diseases. This test breaks down WBCs into categories—such as neutrophils, lymphocytes, monocytes, eosinophils, and basophils—to check for imbalances that may signal health concerns.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw a small amount of blood. The test is quick and usually done in a lab setting.
What the Results Mean
Results show the percentage of each WBC type. For example, high neutrophils might indicate infection, while high eosinophils could suggest allergies or parasites. Your doctor will interpret these results in the context of your symptoms and medical history.
Common Conditions Linked to Abnormal Results
Low or high counts of specific WBCs can signal conditions like infections (e.g., bacterial or viral), autoimmune diseases, or blood disorders. For instance, low lymphocytes may point to HIV or other immune deficiencies.
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.
Doctors use these results to diagnose infections, monitor chronic conditions (like leukemia), or assess immune responses. For example, a high eosinophil count might prompt further testing for allergies or parasitic infections.
Short name
WBC Differential
Frequently asked questions
When might I need this test?
What does a normal result mean?
Can diet or medications affect 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