Total Leukocyte Count
- Sample Type
- Whole Blood
- Fasting
- No
- Unit
- cells/µL
Function
The Total Leukocyte Count (WBC count) measures the total number of white blood cells in a microliter of blood. These cells are the primary defenders of the immune system, responsible for fighting infections, reacting to foreign substances, and responding to tissue injury.
Why it is Ordered
A WBC count is one of the most common lab tests, typically part of a Complete Blood Count (CBC). It is used to screen for infections, inflammation, allergies, and disorders of the bone marrow. It is also used to monitor the body's response to treatments like chemotherapy or radiation.
Associated Conditions
- Infection: Bacterial infections typically cause an increase (leukocytosis), while certain viral infections can cause a decrease (leukopenia).
- Inflammation: Conditions like rheumatoid arthritis or inflammatory bowel disease can raise the count.
- Leukemia: Cancers of the blood-forming tissues can cause extremely high or abnormally low counts of dysfunctional white cells.
- Bone Marrow Suppression: Caused by medications, toxins, or vitamin deficiencies (B12/Folate).
Summary
While the total count provides a snapshot of immune activity, it is often interpreted alongside a 'differential' count, which breaks down the specific types of white cells (neutrophils, lymphocytes, etc.) to pinpoint the exact nature of the physiological stressor.
Check Your Result
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Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
WBC counts are highly sensitive to temporary physiological factors. Intense exercise, high stress, smoking, and pregnancy can all naturally elevate the count. Conversely, many common medications (like corticosteroids) can artificially increase the WBC count, while others (like certain antibiotics or anticonvulsants) can lower it. A second test is often necessary to determine if an abnormal result is a persistent issue or a transient response.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Total Leukocyte Count:
Official Sources
Research & Guidelines
- PubMed: Total Leukocyte Count Clinical GuidelinesNCBI / PubMed
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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