Concerns About Low White Blood Cells And Platelets

What do white blood cells and platelets do for the body? Why is it a concern if these are low?

The four main components of blood are plasma, red blood cells, white blood cells and platelets. Plasma is the liquid part of blood. Red cells are the most numerous blood cells. They contain hemoglobin, which carries the oxygen that the blood circulates throughout the body.

White blood cells, leukocytes, are actually part of the body’s immune system. There are several different types of leukocytes, but they all have the same job — defending the body against infection. When the immune system gets a message that there is an infection or potential infection due to injury or the presence of germs, it martials its forces. It produces extra white cells and sends them off to destroy the invading disease organisms and repel the infection. Pus consists mostly of dead white blood cells.

When the white cell count is low, the body becomes more vulnerable to infection. A low count may be caused by certain types of blood disorders, infection with a virus or certain medications, such as chemotherapy treatment for cancer. The total white blood cell count may not provide enough clues about what is going on and sometimes it is necessary to do a lab analysis called a white blood cell differential, which counts each of the different types of leukocytes.

Platelets, or thrombocytes, have the critical job of stopping bleeding and promoting the healing of wounds. Platelets sort of hang out in circulating blood, not doing much of anything until they encounter a damaged blood vessel that is leaking blood. Then they initiate the clotting process that will eventually stop the bleeding. They release chemicals that help coagulate the blood and they change shape and become sticky, forming a sort of clump, which adheres to the wall of the blood vessel.

There is a fairly long list of conditions that can cause a low platelet count, including AIDS, leukemia, heavy drinking, certain bone marrow disorders, lupus and numerous others. Sometimes, though, no cause is identified. A shortage of platelets is called thrombocytopenia, which can lead to excessive bleeding.

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