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White Blood Cell Count (Absolute)

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

This test measures the number of white blood cells (WBCs) in your blood, focusing specifically on the total count of these immune system cells.

Quick summary

["This test helps assess your immune system’s strength and detect infections or other health issues."]

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

Key facts at a glance

LOINC
82883-0
Short code
LAL WBC 4-MUP substrate-cCnt
Synonyms
LAL WBC 4-MUP substrate-cCnt
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
mu-palmitate-substrate
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

Why This Test Matters

White blood cells are crucial for fighting infections, healing wounds, and protecting your body from diseases. An abnormal count can signal conditions like infections, inflammation, or certain blood disorders.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw a blood sample. It usually takes a few minutes, and you may feel a slight pinch.

What the Results Mean

Results show the total number of white blood cells per microliter of blood. High counts may indicate infection, stress, or inflammation, while low counts could signal immune deficiencies or other health problems.

Common Conditions Monitored

This test is often used to diagnose or monitor infections (like pneumonia or urinary tract infections), autoimmune diseases, or conditions affecting the bone marrow.

Reference range

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

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

WBC Absolute Count

Frequently asked questions

How often is this test done?
This test is typically performed as part of routine blood work, during illness, or when monitoring conditions like cancer, autoimmune diseases, or chronic infections. Your doctor will determine the need based on your symptoms and medical history.
What are the possible side effects of this blood draw?
Most people experience minimal discomfort, such as a small bruise, slight pain, or swelling at the injection site. Rarely, there may be a slight fever or headache, but these usually resolve quickly.
Can I eat or drink before this test?
Yes, you can eat and drink normally before this test unless your doctor specifies otherwise. No fasting is required.
  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