Leucocytosis is an elevation in the white blood cell count. In some cases, an elevated white blood cell count is the body’s normal response to inflammation or infection. When there is inflammation or infection, the body makes more white blood cells because they fight off the infection. Once the infection or source of inflammation is eliminated, the white blood cell count should return to normal. In some cases, the white blood cell count does not return to normal and no infection or source of inflammation can be found. This may indicate something more serious, so your physician may refer you to a hematologist. An elevation in the white blood cell count is very non-specific and does not point to one single abnormality. The hematologist will need to do further testing to determine the cause of the elevation.