A CBC is also called a complete blood count. It is used to evaluate the three different blood cells that we have in our body. White blood cells are one type of blood cell. These blood cells are a key part of the body's immune system. They are part of the body's defense system used to fight off infection. In a healthy person, the number of white blood cells increases when we have an infection like pneumonia or a urinary tract infection
. Occasionally, the level of white blood cells can be too high or too low with certain types of blood cancers, like leukemia and lymphoma.
A CBC also tests the number of red blood cells in the body. These are the cells that carry oxygen all around the body. The number of red blood cells can be low in people with excessive bleeding. When the level of red blood cells is reduced, this is called anemia.
Finally, the CBC evaluates the number of platelets circulating in the body. These cells are needed to help the blood clot.
A primary care doctor
(blood specialist) will use the CBC as the principal test to evaluate the blood cell lines, including the white blood cells, in the body.