Normal White Blood Cell Count

Normal White Blood Cell Count (Normal WBC Count)

Normal White Blood Cell Count or Normal WBC Count varies for each age group. Generally speaking, the Normal White Blood Cell Count tends to decrease by aging, however, the Neutrophil WBC increases by aging, except in the care of newborns where infants are normally born with a relatively high Neutrophil count that drops dramatically during the first 2 weeks. The White Blood Cells Count (WBC Count) is a medical test for counting the white blood cells that are circulating with the blood. The count doesn’t include the white cells that are living in the tissues, bone marrow, thymus or spleen.

The white cells count is important to detect changes (Alternations) on the Normal White Blood Cells Count that are circulating with the blood. Since white cells are responsible in defending the body from the invading foreign bodies, a high white blood cells count or a low white blood cells (Leukopenia) can be a sign of having an infection that the body is resisting or fighting.

Before thinking of infections to be the cause white blood cells count alternations, it is also important to understand that alternations to the normal counts of white blood cells can also be an evidence of producing white blood cells higher or lower than normal levels due to immune system disorders, boon marrow deficiency, spleen disease, or exposure to radiation.

White blood cells count can also increase because of severe physical or emotional stress, pregnancy, having anemia or leukemia, or taking drugs that increase the WBC count such like Aspirin.

An understanding of the patients surround environment, habits, and the types of drugs they may be taking would be helpful with the results of the white blood cells to determine the cause of the count alternation. Further examination and more tests may be required with studying the results to have a clear picture of real causes of the alternation.

The Normal WBC Count ranges between 4,500 and 10,000 white blood cells per microliter (µL) of blood. To visualize it, a microliter is a cubic millimeter, or a cube of blood that is 1 mm in length width and height.

The Normal White Blood Cells Count is expected to be high at younger age and to decrease as the person gets older. The highest count is expected to be seen at the first day of birth and gets lower as the person grows up; However, the Neutrophils and Lymphocytes are special cases. The Neutrophils count will decrease dramatically at the age of 2 weeks to be less than the neutrophils count of an adult, then the neutrophils count starts to increase again by the person ages. On the other hand, the Lymphocytes count will increase and exceed the neutrophils count during the first years of childhood and then decreases by aging.

The count of each white blood cells type is very helpful since each WBC type is responsible for fighting different kinds of microorganisms, in other words the increase or decrease  in production or consumption of each type is depend on the bodies the white bloodit fights. For example an increase in the Neutrophils count can be a sign of pyogenic bacterial infection (Bactria that cause pus) while an increase in the Monocytes count can be a sing of non-pyogenic bacterial infections such like Syphilis.

The following table shows the age related normal white cell count for each type.

White Cell Type Percentage Count

Normal Neutrophils Count

Normal Segmental (mature) Neutrophil Count

Infant, first day 32 to 62 8870
Child, 1 year 13 to 33 2600
Child, 10 years 31 to 61 3700
Adult, Over 21 36 to 66 3800

Normal Band (immature) Neutrophil Count

Infant, first day 10.2 to 18.2 2580
Child, 1 year 5.1 to 11.1 990
Child, 10 years 5 to 11 645
Adult, Over 21 5 to 11 620

Normal Eosinophil Count

Infant, first day 2.4 450
Child, 1 year 2.6 300
Child, 10 years 2.4 200
Adult, Over 21 2.7 200

Normal Basophil Count

Infant, first day 0.5 100
Child, 1 year 0.4 50
Child, 10 years 0.5 40
Adult, Over 21 0.5 40

Normal Lymphocyte Count

Infant, first day 26 to 36 5800
Child, 1 year 46 to 76 7000
Child, 10 years 28 to 48 3100
Adult, Over 21 24 to 44 2500

Normal Monocyte Count

Infant, first day 5.8 1100
Child, 1 year 4.8 550
Child, 10 years 4.3 350
Adult, Over 21 4 300


To count white blood cells, a blood drop is placed on one end of a microscope slide and the other end spreads the blood to create a one cell layer thin blood smear. There are 2 types of white blood cell count:

Differential white blood Cell Count:

The blood smear is stained by a polychromic solution (Wright’s stain) that contains acidic and basic dyes. The components of cellular structure for each type will then absorb those dyes in different levels based on their unique chemical characteristics and each type will appear in a unique looking colorful group of cells, this way it would will easier to distinguish each type of cells from the other types. The percentage of each cell type is then determined based on the big picture of all the cells together.

The goal here is to determine if there is a differential alternation in the count of certain type of white cells compared to the other types. The actual count is not what we are looking for here since this method will give an idea if there is a significant increase or decrease of a specific type. For example, in the case of Basophil, differential white blood cells count will be more helpful to determine alternations than knowing the absolute count of the Basophils.

Absolute White Blood Cell Count:

This method is used if the count specific type of the white cells would be helpful in diagnosis. In this case the blood smear is stained using a fluid that only stains the white cells type in interest. This fluid usually lyses the red blood cells and the other white blood cells that are not in interest.  Some fluids may not lyse the other white cells, but leave them unstained.