erythrocytaeinia
An abnormal increase in the number of red blood cells per mm3 of blood. The red blood cell count varies considerably among healthy people, but there are normally about = million per mm3. A figure above 6 million per mm3 indicates polycythaemia. Relative polycythaemia occurs when the total number of red blood cells in the circulation is normal, but the volume of circulating fluids has decreased due to dehydration, injury, or disease. Absolute polycythaemia occurs in response to an oxygen deficiency, for example, as a part of altitude acclimatization and in those suffering from cardiorespiratory disease. Compare anaemia. See also blood doping.
