by Wendy Pettit

Created on: August 15, 2008   Last Updated: August 28, 2008

What are white blood cells and why are they important?

White blood cells have the important job of fighting germs and infections that may infiltrate the body. Detecting low white blood cells is vital in determining such conditions as bone marrow depression, certain viruses, toxic reactions, German measles, infectious hepatitis, radiation therapy, and chemotherapy.

Tests that detect low values of white blood cells vary according to the type of cell affected. White blood cells, known as leukocytes, are broken down into different groups, each have a specific function. The specific groups are monocytes, lymphocytes, and granulocytes, which include neutrophils, eosinophils and basophils. These cells can consume other cells.

Complete Blood Count (CBC)

A physician will order a complete blood count or CBC, if suspicion of low white blood cells is present. The CBC calculates the formed elements of the blood, giving the physician an informative take on what steps to take next. Usually included with the CBC is the white blood count (WBC), which measures the relative number of white blood cells.

Coulter Counter

The tool used to count the white blood cells is called a coulter counter. This device is used by adding the white blood cells to an electrically charged solution. The treated cells are then counted and sized. The cells are further observed by charting and graphing the changes.

Peripheral Blood Smear

A peripheral blood smear is another tool used to detect low white blood cells. This test is used to determine the percentage of the different types of white blood cells in the blood; a procedure referred to as a differential white blood count. This process entails counting at least one hundred white blood cells to which cells are affected. The blood differential test provides vital information regarding cell structure and presence of immature cells.

Absolute Neutrophil Count (ANC)

Absolute neutrophil count (ANC) is actually a calculation rather than a test. Nonetheless is provides important information doctors will need to perform needed treatment and procedures on their patients. The calculation is accomplished by multiplying the white blood cells present in the blood, by the total percent of neutrophils.

The results of the (ANC) give health-care providers a tool to use in further treatment of patients. In particular, doctors can determine whether patients are able to continue chemotherapy, by the use of this test.

Leukocyte Scan

Once tests reveal a low white blood cell count or presence of infection or fever, then the next step is to determine the cause of the depletion. Certain tests can pinpoint where the exact infection or inflammation is located in the body. One particular test, called the leukocyte scan, will provide such information using radioactive material.

The scan, also referred to as a nuclear scan, has the ability to highlight the problem areas using the white blood cells. This involves separating the white blood cells from the whole blood and treating them with a radioactive material. After treated, the cells put back into the bloodstream for further screening. This procedure allows visual conformation of the infection or inflamed area.

Detecting low white blood cells is important for many reasons. It allows a conclusion to unanswered questions. Is there an infection? Is the person strong enough to withstand lifesaving treatments? Are there certain diseases or bone marrow abnormalities? All of these questions can be answered through white blood cell testing.

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