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Total White Blood Cell Count (WBC) with Differential (Serum/Plasma Preparation)

Published: August 9, 2026Updated: August 16, 2026

This test measures the types and proportions of white blood cells in your blood, helping identify infections, inflammation, or immune system issues.

Quick summary

Understanding your blood’s immune cell balance can reveal hidden health concerns.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
61227-5
Short code
White Birch IgE/IgE total %
Synonyms
White Birch IgE/IgE total %
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 This Test Measures

A differential white blood cell count breaks down the five main types of white blood cells (neutrophils, lymphocytes, monocytes, eosinophils, and basophils) into percentages. This helps doctors assess immune responses, infections, or chronic conditions like allergies or autoimmune diseases.

Why It Matters in Your Health

Abnormal counts or ratios can signal infections (e.g., high neutrophils), chronic inflammation (e.g., high monocytes), or immune disorders (e.g., low lymphocytes). It’s often used alongside a total WBC count for deeper insights.

Common Reasons for Testing

Doctors may order this test if you have symptoms like fever, fatigue, frequent infections, unexplained weight loss, or if they suspect conditions like leukemia, lupus, or severe allergies.

Sample Preparation and Testing Process

A simple blood draw is used. The sample is processed to separate white blood cells, then analyzed under a microscope or automated counter to count and classify each cell type.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

WBC Differential

Frequently asked questions

How might my results affect my treatment?
Your results will guide your doctor’s decisions. For example, a high eosinophil count might suggest allergies or parasitic infections, while a low neutrophil count could indicate immune suppression or bone marrow disorders. Always discuss your specific findings with your healthcare provider.
Can I influence my test results?
Avoid strenuous exercise, infections, or certain medications (like steroids) 24 hours before testing. Smoking, stress, or recent illness may also temporarily affect results.
What if my results are outside normal ranges?
If your differential shows unusual patterns, your doctor may recommend further tests (e.g., blood cultures, skin tests) or adjust treatments like antibiotics or immune-modifying drugs.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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