Erythrocytosis (Polycythaemia): Definition, Causes & Treatment

Erythrocytosis is having a high concentration of red blood cells. Your levels may be high for many reasons. Some causes, like dehydration, are less concerning than others, like polycythemia vera, a serious blood disorder. Getting diagnosed and receiving treatment can prevent complications associated with erythrocytosis, like life-threatening blood clots.

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Erythrocytosis involves having a higher-than-normal concentration of red blood cells (erythrocytes) in your blood. Your blood consists of solid parts, including red blood cells, white blood cells and platelets. It also includes a liquid portion called plasma. Erythrocytosis describes having too many red blood cells (a solid part) in relation to plasma (the liquid part).