Elevated hematocrit levels may be caused by dehydration; lung disease or smoking; or congenital heart disease, according to the American Association for Clinical Chemistry. Polycythemia vera, a condition where the body overproduces red blood cells, and kidney tumors that produce high levels of erythropoietin may also cause high levels.
Those living at high altitudes also tend to have higher levels of hematocrit compared to those living at lower elevations, notes the American Association for Clinical Chemistry. The body compensates for the lower level of oxygen in the air by producing more red blood cells, which in turn elevate hematocrit. Recent blood transfusions also impact hematocrit levels, adds Mayo Clinic.
Treatment for elevated hematocrit levels varies according to the cause, states eMedicineHealth. For example, a person with polycythemia vera may undergo blood letting to thin the blood and prevent complications from the condition. Smokers may be urged to quit, and those with lung disease are treated as befits their particular disease.
Hematocrit is the proportion of red blood cells that make up a person's total blood volume, explains Mayo Clinic. It is expressed as a percentage of total red blood cells. Normal values for adult males range from 38.8 to 50 percent. For adult females, the normal range is 34.9 to 44.5 percent. These normal ranges may vary somewhat from lab to lab, though proper reference values are always included on the lab report.