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White blood cells

White blood cells (leukocytes) are part of the immune system. Their role is to protect the body. There are five major types of white blood cells: neutrophils, eosinophils, basophils, lymphocytes, and monocytes. Each type of white blood cell plays a specific role in the body.

What is the purpose of this test?
  • To assess whether your blood cell production system is working properly
  • To follow up with individuals taking certain medications
  • To diagnose various health problems, including:
    • Infections
    • Inflammatory conditions (e.g., rheumatoid arthritis)
    • Immune system disorders
How to prepare? No preparation needed.
Reference values* 3.5-10.5 x 109/L
Associated tests The other tests in a complete blood count are typically done at the same time. These tests measure different parts and features of your blood, including the following:
How is it done? A blood sample is drawn, usually from a vein in the arm.
How long before I get the results? Results are usually ready in a day. It may take longer to receive your results.
* These values are presented for information purposes only. As different laboratories may have different target values, the lab report usually specifies the values used for the test. It should also be noted that test results must be interpreted based on factors such as age, sex, and health condition. Values outside of this range may be considered normal for some individuals.

What does an abnormal test result mean?

High white blood cell count:

  • Infection
  • Trauma or shock (e.g., surgery, burns)
  • Inflammatory condition
  • Certain cancers (e.g., leukemia)

Low white blood cell count:

  • Vitamin B12 or folic acid deficiency
  • Certain liver diseases
  • Certain spleen diseases
  • Bone marrow disorders, including certain types of cancer

Factors that may influence test results

  • Certain medications (e.g., chemotherapy, immunosuppressants, corticosteroids, clozapine)
  • Pregnancy
  • Asplenia (having no spleen)

What you should know before going for this test

When you go in for a blood test or any other medical exam, it's always a good idea to bring a complete list of any prescriptions, over-the-counter medications, or natural health products you're taking. Unless otherwise advised, it's best to take your medications as usual on blood test days. If in doubt, don't hesitate to talk to your healthcare professional.

© Copyright Vigilance Santé

The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.

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