Medically reviewed on June 16, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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White blood cells, also known as “leukocytes,” are a part of the body’s immune system. These cells comprise only about 1 percent of the complete blood count, but they serve a necessary role. They are the body’s first line of defense against bacteria, viruses, and other harmful microbes, and they are constantly at work protecting you from these microbes and healing any infections or damaged tissue .
Leukocytes are synthesized in the bone marrow and stored in the lymph tissues and blood. Once the body identifies a microbial threat, the immune system signals white blood cells to rush to the affected area to contain the infection, prevent illness, and to destroy the invading threat .
While this process is highly regulated, you may potentially have a low white blood cell count, which can contribute to a handful of other issues such as an autoimmune disorder. Therefore, it makes it important to take a complete blood count or CBC test. Learn more about the symptoms to look for with low white blood cell levels below.
Low white blood cell count is medically known as “leukopenia,” and it is almost always related to significant reductions in neutrophils, a type of white blood cell. Neutrophils are designed to fight specific infections, particularly bacterial infections, and low neutrophil count is known as “neutropenia" .
So what happens when your white blood cells are low? Most people with a low white blood cell count will not experience any symptoms. Typically, when white blood cell levels are abnormally low, you may be more prone to infections. Common signs of an infection are chills, sweating, and a fever over 100.5° Fahrenheit .
A low neutrophil count will usually result in persistent fevers and infections affecting various organ systems. Neutropenia can make you more prone to:
Low white blood cell counts can occur in anyone of any age, and it is typically a sign of more serious underlying health problems. Leukopenia is usually only identified via tests for a condition that you are already experiencing . Most commonly, a low white blood cell count is mainly caused by certain treatments for cancer, including chemotherapy and radiation therapy .
A complete blood cell count essentially measures the amount of specific blood cell types in the blood. What constitutes a low white blood cell count varies from person to person, test to test. In adults, a count of less than 4,000 white blood cells per microliter of blood is liable for a leukopenia diagnosis. However, some people who are otherwise healthy may have counts lower than this and not experience any complications .
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