What is White Blood Cell Count & Differential?

What is White Blood Cell Count & Differential?

White blood cell count plays a vital component of your immune system. They protect your body against infections and invading organisms. There are five types of white blood cells in the human body:

  • Neutrophils
  • Lymphocytes
  • Monocytes
  • Eosinophils
  • Basophils

A disease or health condition will affect each of these white blood cells differently.

A white blood cell count is used to determine the number of white blood cells in a person’s blood. On the other hand, a white blood cell count differential determines the percentage of each kind of white blood cell in your blood. A WBC differential also detects immature white blood cells and abnormalities. It is important to note that both immature white blood cell and white blood cell abnormalities indicate potential issues.

A white blood cell count is also known as a leukocyte count. On the other hand, a WBC differential may also be called a leukocyte differential count.


What is the physiological significance of a white blood cell count and differential?

Your healthcare provider may order a WBC count and differential if they suspect that you have any of the following conditions:

Using both tests, your doctor can determine the exact cause of your symptoms – whether they are due to very high or deficient white blood cell levels. This will help them to diagnose your condition. WBC counts are also significant in monitoring certain illnesses and disease processes.


How is a WBC count and differential done?

A WBC count or differential does not require any special preparation. However, your healthcare provider may advise you to avoid certain medications, such as vitamins or over-the-counter supplements. It is worth noting that both over-the-counter and prescription medicines can affect white blood cell counts.

To do a WBC and differential count, your healthcare provider will need to draw a sample of blood from you. The blood is typically drawn from a vein in your hand or the bend of your arm. After collecting the blood, it is sent to the lab for analysis.


Are there any risks associated with a WBC count and differential?

There are very few risks associated with a WBC count and differential. There’s nothing more to expect other than bruising at the puncture site. Sometimes, one may feel a stinging sensation as the blood is drawn. Others may feel lightheaded or sick during or after the blood draw. If you think of any of these symptoms, disclose them to your nurse or doctor and remain seated until you are relieved.

In rare cases, drawing of blood can cause a hematoma – accumulation of blood under the skin. Sometimes, an infection may develop in the skin at the site where the blood was collected, but this is also rare.


What to expect after a WBC or differential?

Depending on the tests ordered, you may have to wait for a couple of days to get your result. A single WBC or differential count does not say everything wrong in your body. However, both tests will help your healthcare provider find out the probable cause of your symptoms. Differential results may indicate any of the conditions highlighted below:

An increase in neutrophil count may be a result of:

  • Infection
  • Acute stress
  • Gout
  • Pregnancy
  • Trauma
  • Thyroiditis
  • Rheumatoid arthritis

A decrease in neutrophil count may be caused by:

  • Exposure to radiation
  • Influenza
  • Bacterial infection
  • Viral illnesses
  • Chemotherapy
  • Anemia

Increased lymphocyte count may be caused by:

  • Leukemia
  • Mononucleosis
  • Chronic infection
  • A viral infection, like measles or mumps

A decrease in lymphocyte count may be caused by:

  • Leukemia
  • Chemotherapy
  • Sepsis
  • HIV infection
  • Exposure to radiation, either from therapy or accidentally

A rise in monocyte count may be caused by:

  • Tuberculosis
  • Chronic inflammatory disease
  • Viral infections like mononucleosis, mumps, and measles

A reduction in monocyte count may be caused by:

  • Skin infections
  • Bone marrow disorder
  • Chemotherapy
  • Bloodstream infection

Increased eosinophil count may be caused by:

  • Parasitic infection
  • An allergic infection

A decreased basophil count may be due to an acute allergic infection.

Your healthcare provider will explain your test results to you, and if need be, create a treatment plan most suited for your condition. There may be a need for additional tests to confirm a diagnosis.


Image by Lela Maffie from Pixabay

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