White Blood Cell Differential with Automated Counting
This test measures the types and proportions of white blood cells in your blood, using an automated machine to count them.
["It helps identify infections, immune responses, or other blood disorders by showing how many of each type of white blood cell you have."]
Key facts at a glance
- LOINC
- 99776-7
- Short code
- WBC # BAL Auto
- Synonyms
- WBC # BAL Auto
- 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
- Method
- automated-count
- 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 Does This Test Measure?
Your blood contains several types of white blood cells (WBCs), each with a specific role in fighting infections or responding to injury. This test automatically counts and compares the percentages of five main types: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. These numbers can help doctors diagnose conditions like infections, allergies, or blood disorders.
Why Might You Need This Test?
Doctors may order this test if you have symptoms like frequent infections, unexplained fevers, fatigue, or swelling. It’s also used to monitor conditions like leukemia, immune deficiencies, or chronic illnesses like lupus or rheumatoid arthritis.
How Is the Test Performed?
A small blood sample is drawn from a vein, usually in your arm. The sample is then sent to a lab where an automated machine analyzes the blood cells and provides the differential counts.
What Are the Results Typically Used For?
The results help doctors assess your immune system’s balance. For example, a high neutrophil count might suggest an infection, while a low lymphocyte count could indicate a weakened immune response. Your doctor will interpret the results 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.
Abnormal white blood cell counts can signal underlying health issues. For instance, an elevated eosinophil count may point to allergies or parasitic infections, while a shift to immature white blood cells (left shift) could indicate severe infection or bone marrow problems. Regular monitoring of these counts helps manage chronic conditions and guide treatment decisions.
Short name
WBC Differential (Auto)
Frequently asked questions
How long does it take to get my results?
What does each type of white blood cell represent?
Can I eat or drink before 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