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White Blood Cell Count (WBC) with Differential Blood Profile

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

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).

Quick summary

["Understanding your immune system’s cell composition helps identify infections, inflammation, or blood disorders."]

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

Key facts at a glance

LOINC
47281-1
Short code
WBC # BldCo
Synonyms
WBC # BldCo
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

A WBC count helps doctors assess your immune health, detect infections, or evaluate conditions like leukemia, autoimmune diseases, or allergies. The differential provides deeper insight into which types of white blood cells are present.

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 blood. If you’re nervous, let your provider know—they can help.

What the Results Mean

Your results will show your total WBC count and the percentage of each cell type. Abnormal counts can signal infections, immune disorders, or other health issues. Your doctor will interpret these results in the context of your symptoms and medical history.

Common Reasons for Testing

Doctors may order this test if you have symptoms like fever, fatigue, frequent infections, unexplained weight loss, or signs of bleeding. It’s also used for routine check-ups, monitoring chronic conditions, or before certain treatments.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

WBC with Differential

Frequently asked questions

What does a high or low WBC count indicate?
A high WBC count may suggest an infection, inflammation, or a condition like leukemia. A low WBC count could mean your immune system isn’t working well, increasing infection risk. The differential helps pinpoint which cell types are affected.
How often should I get this test?
Your doctor will determine how often you need this test based on your health needs. Some people get it yearly for routine check-ups, while others may need it more often if they have ongoing medical conditions.
Can I eat or drink before this test?
You can eat and drink normally before the test unless your doctor specifies otherwise. Avoiding alcohol or certain medications may be advised if they could affect your results.
  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