This test measures the number of
white blood cells (WBCs) in your blood. White blood cells are also called leukocytes.
Your bone marrow makes white blood
cells and release them into the bloodstream. White blood cells help you fight infection.
They are part of your body's immune system, which keeps you healthy and makes you
when you get sick. White blood cells work to destroy any foreign virus, fungus, or
bacteria that enter your body.
When you get sick, your white blood
cell count is higher than normal. This is because your body is releasing more of these
cells to fight the infection. But if you have certain illnesses like HIV or cancer, your
white blood cell count can drop to very low levels. It can also drop if you are on
medicine that weakens your immune system. This includes medicines, such as
White blood cells are divided into
5 main types:
This test measures the total count
of all types of white blood cells. It does not measure the levels of each type of