An elevated white blood cell count is a laboratory findings on analysis of your blood. One of the most common blood tests that is obtained in the ER is a CBC or a Complete Blood Count. It looks at the amount of red blood cells, platelets and white blood cells in your blood.
White blood cells are a part of the body's immune system. The white blood cell count usually increases when your body is experiencing an inflammatory process. This is most commonly seen in setting of infection. For example, if a patient develops pneumonia
(infection of the lungs), the white blood cell count will be high, until the pneumonia is treated, at which point the white blood cell count comes down.
Having a high white blood cell count does not necessarily meant that you have an infection. It is somewhat non-specific of a finding when analyzed by itself. A history, physical exam, other labs and imaging may be needed to pinpoint the source of the increased white blood cell count.
In other words, an elevated white blood cell count tells you something is wrong, but on its own, won't tell you what or where the problem lies. Thus it is very important to see your primary care doctor
and undergo appropriate testing, starting from the physical exam to establish a diagnosis and cause of the elevated white blood cell count.