Contributed by – Preksha Buttan

What is the WBC test?

White blood cell (WBC) test measures the number of white blood cells in the blood. White blood cells, also called leukocytes, are an important part of the body’s defence system. They help in the protection against infections, inflammation and allergic reactions. Having a higher or lower number of WBCs than the normal may indicate the presence of some underlying medical condition.

 

Who should get tested?

The doctor may order a WBC test in case the following symptoms are noticed – 

  • Body aches
  • Fever
  • Chills
  • Headaches
  • Signs and symptoms of inflammation

The testing may also be done if the signs and symptoms associated with the blood disorder, autoimmune disorder or immune deficiency are present.

Besides, WBC test is performed periodically or as a part of complete blood count (CBC) test if a diagnosis of conditions affecting WBC count has already been made. This is done to monitor the effectiveness of the treatment. 

 

Why is the WBC test needed?

There are five major types of WBCs – neutrophils, lymphocytes, eosinophils, monocytes and basophils. All of these cells are an important part of the immune system. They work together to fight off infections by attacking the bacteria, viruses and germs that invade the body. 

Besides inflammation and infections, conditions like cancer or immune disorder can affect the production of WBCs. Therefore, an abnormal WBC count can help the doctor make an early diagnosis of the possible condition with the help of further testing.

 

What does WBC test results mean?

Normal ranges of WBC count are:

AGE RANGE WBC COUNT (per mcL of blood)
Newborns 9,000 – 30,000
Children under 2 6,200 – 17,000
Children over 2 and adults 5,000 – 10,000

Note that these ranges are for reference only and may vary from lab to lab. Hence, always get your reports checked by the doctor to correctly understand what they mean for you.

Typically, a low WBC count, a condition called leukopenia, is triggered by – 

  • HIV
  • Autoimmune disorders
  • Bone marrow disorders
  • Lymphoma
  • Severe infections
  • Liver diseases
  • Radiation therapy
  • Certain medications

And, a high WBC count, called leukocytosis, is triggered by – 

  • Smoking
  • Infections
  • Tumours
  • Leukaemia
  • Inflammatory conditions
  • Stress
  • Exercise
  • Tissue damage
  • Pregnancy
  • Allergies
  • Asthma
  • Certain medications

 

How is the test done?

White blood cell count test is a simple blood test for which a small sample of blood is needed. It is collected by a trained sample collector from a vein in the arm. The process is quick and relatively painless. Any kind of special preparation or fasting before the sample collection is not needed. However, certain existing conditions and medications can influence your test results. Therefore, if there is any pre-existing medical condition or you take any medication regularly, then it is recommended that you inform your doctor about that in advance.

 

Take the WBC test now!