Causes of high granulocyte count?

Many causes: Anything from an infection to a serious blood disease to just a little bit of stress. I can triple my granulocyte count with a 20-minute cold shower as my neutrophils leave the walls of my blood vessels and enter my bloodstream to see what's happening. If the neutrophils are immature (left-shift) or look very activated (toxic granulation) there's likely to be an important infection.

Acute infection: Stress response with illness, certain meds likel steroids and lithium, heavy smoking (carbon monoxide excess), chronic and acute leukemia.