High White Blood Cell Count

A high white blood cell (WBC) count, also known as leukocytosis, is a condition where the number of white blood cells in the blood exceeds the normal range. The normal range for WBC count is typically between 4,000 and 11,000 cells per microliter (µL) of blood.

Causes

There are several possible causes of a high WBC count, including:

  • Infections: Bacterial, viral, or fungal infections can cause an increase in WBC count as the body tries to fight off the infection.
  • Inflammation: Conditions such as arthritis, inflammatory bowel disease, and other autoimmune disorders can lead to a high WBC count.
  • Allergic reactions: Severe allergic reactions can cause an increase in WBC count.
  • Cancer: Certain types of cancer, such as leukemia or lymphoma, can cause a high WBC count.
  • Medications: Some medications, such as corticosteroids and immunosuppressants, can affect WBC count.
  • Stress: Physical or emotional stress can cause an increase in WBC count.

Symptoms

The symptoms of a high WBC count can vary depending on the underlying cause. Some common symptoms include:

Diagnosis

A high WBC count is typically diagnosed through a complete blood count (CBC) test, which measures the levels of different types of blood cells, including white blood cells. A healthcare provider may also perform other tests, such as:

  • Blood cultures to check for infection
  • Imaging tests, such as X-rays or CT scans, to look for signs of inflammation or cancer
  • Biopsy to examine tissue samples for abnormal cell growth

Treatment

The treatment for a high WBC count depends on the underlying cause. Some possible treatments include:

Complications

If left untreated, a high WBC count can lead to complications, such as:

  • Sepsis, a life-threatening condition that occurs when the body's response to an infection becomes uncontrolled
  • Organ damage, such as kidney or liver damage, due to chronic inflammation
  • Cancer progression, if cancer is present

Frequently Asked Questions (FAQs)

What is a high white blood cell count?
Typically above 11,000 cells per microliter, but can vary depending on laboratory and individual factors.

What causes a high white blood cell count?
Infection, inflammation, stress, or diseases such as leukemia, among other possible causes.

Is a high white blood cell count always a sign of infection?
No, it can be caused by various conditions, including non-infectious ones.

Can a high white blood cell count be a sign of cancer?
Possibly, in some cases, such as leukemia or lymphoma, but not exclusively.

How is a high white blood cell count diagnosed?
Through a complete blood count (CBC) test, which measures the levels of different blood cells.

What are the symptoms of a high white blood cell count?
May include fever, fatigue, weakness, or no noticeable symptoms at all.

Can a high white blood cell count be treated?
Treatment depends on the underlying cause, and may involve antibiotics, anti-inflammatory medications, or other therapies.

Is a slightly elevated white blood cell count always a concern?
Not necessarily, as minor elevations can occur due to various transient factors.

Can a high white blood cell count be prevented?
Possibly, by preventing infections and managing underlying conditions that may contribute to it.

When should I see a doctor about a high white blood cell count?
If symptoms persist or worsen, or if the cause of the elevation is unknown or unclear.

Article last updated on: 18th October 2025.
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