Is 20000 high for a white blood cell count?

A white blood cell count (WBC) of 20,000 is high. The normal range for WBC is 4,500 to 11,000 cells per microliter of blood. A WBC count that is higher than normal may be a sign of an infection, inflammation, or other medical condition. If you have a WBC count of 20,000 or higher, you should see your doctor right away to determine the cause and receive appropriate treatment.