What cause your ref blood cell count to be high?

Many causes: Dehydration can cause high red blood cell count. It may be a normal finding in people living at high altitude. People with cyanotic heart disease also have high counts. Smokers and people with chronic lung disease also may have high counts. Chronic carbon monoxide poisoning is an other cause. More seriously, a form of blood cancer can cause very high counts - namely polycythemia vera.