Understanding White Blood Cell Count – Normal, High, & Low

Complete blood count “cbc”

The complete blood count is an important follow-up and screening tool we have all used more than once. It is one of the first exams doctors ask when there’s an infection or any other alteration. The complete blood count includes the white blood count, which is an estimate of how many white blood cells there are in your blood.

The white blood count is very important because these cells have a key role in defending your body against infection. White blood cell creation and release in the blood are triggered and stimulated during infection. A functioning immune system will respond against disease by increasing the total count of white blood cells. Thus, it is a helpful measure to see how is your immune system reacting, and what type of disease your body is trying to counter.

In this type of test, a sample of your blood will be taken, and you don’t need any special preparation to evaluate your white blood cell count. Thus, you can use this exam in emergency settings, and it won’t be altered according to your eating patterns or any fasting state.

In this article, we will go through white blood cell count in detail and give you an insight of what to expect in cases of normal white blood cell count, and how to interpret abnormal results.

Normal white blood cell count

White blood cells
White blood cells

To understand white blood cell count, it is important to know what it measures. There are 5 main types of white blood cells. They are:

  • Basophils: It is less abundant compared to other white blood cells, and they are typically responsible for allergic reactions. The normal proportion of basophils is 0.5% of the total number of white blood cells.
  • Eosinophils: They are mainly phagocytic cells, which means they are attracted and swallow microorganisms to destroy them. These cells are usually found as 1 to 3% of the total number of white blood cells.
  • Lymphocytes: There are many types of lymphocytes, but all of them look the same under the microscope and are counted as a total lymphocyte count. They are very abundant in the blood, representing up to 30% of the total number of white blood cells.
  • Monocytes: They are also known as macrophages when they migrate to the tissues, but in the blood, they are called monocytes. These represent up to 8% of the total number of white blood cells.
  • Neutrophils: By far the most common white blood cells, and the first line of defense against disease. Neutrophils destroy bacteria and fungi with a series of enzymes and turn into pus when they die in battle. In normal settings, they represent 60 to 70% of the total white blood count.

The normal white blood cell count is 4,500 to 11,000/μL, but the normal value range may vary from one laboratory to another.