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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 in your blood, which helps assess your immune system and detect infections or inflammatory conditions.

Quick summary

["Your immune health depends on white blood cells; abnormal counts may signal infection, immune disorders, or other health issues."]

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

Key facts at a glance

LOINC
1766-5
Short code
Num Aldost Recep WBC
Synonyms
Num Aldost Recep WBC
Category
coagulation
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
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 It’s Done

Doctors order a white blood cell count to diagnose or monitor conditions like infections (such as pneumonia or urinary tract infections), autoimmune diseases (like lupus or rheumatoid arthritis), blood disorders (such as leukemia), or to check for signs of inflammation in your body.

What to Expect

A simple blood draw is used to collect your sample. The test is quick and painless, and results are typically available within a few hours or the next day. No special preparation is needed.

Normal vs. Abnormal Results

While reference ranges can vary by lab, a normal white blood cell count usually falls within a broad range. High counts (elevated) may indicate infection, stress, or inflammation, while low counts (reduced) could signal immune suppression, bone marrow issues, or certain medications.

Common Conditions Affecting Results

Elevated white blood cells may be seen in infections (bacterial, viral, or fungal), chronic illnesses like diabetes or heart disease, or after physical stress (e.g., exercise). Reduced counts may occur with immune deficiencies, chemotherapy, or severe infections.

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 Count

Frequently asked questions

What does a high white blood cell count mean?
A high WBC count often signals an active infection, inflammation, or an overactive immune response. For example, a bacterial infection like appendicitis or a severe allergic reaction may raise your WBC count. Your doctor will consider your symptoms and other test results to determine the cause.
What does a low white blood cell count mean?
A low WBC count may indicate a weakened immune system, which can happen due to certain medications, autoimmune diseases, or conditions like HIV/AIDS. It can also occur after chemotherapy or radiation therapy. Your doctor may recommend further testing to identify the underlying cause.
Can diet or lifestyle affect white blood cell counts?
Yes, certain foods and habits can influence your WBC count. For example, a balanced diet rich in vitamins (like vitamin C and D) and lean proteins supports immune function. Smoking, chronic stress, or poor sleep can also temporarily affect your immune response, but they don’t directly alter the test results themselves.
  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