Conditions that cause high hematocrit levels include congenital heart disease, pulmonary fibrosis and polycythemia vera, explains MedlinePlus. High hematocrit levels may indicate failure of the right side of the patient's heart, abnormal increase of his read blood cells and low oxygen levels in his blood.
High hematocrit levels mean that the red blood cell count is abnormally high, explains MedicineNet. High red blood cell counts are common in individuals who live in high altitude areas. Chronic smokers may also have high hematocrit levels. Dehydration may cause a false high hematocrit due to lower fluid volume. Athletes who abuse the blood-doping drug erythropoietin may have high hematocrit results.
Congenital heart diseases may reduce oxygen levels in the blood, and the body compensates by creating more red blood cells, according to Lab Tests Online. Tumors in the kidney produce excess erythropoietin, which causes high hematocrit levels.
A disorder of the bone marrow known as polycythemia vera may cause a high hematocrit reading, according to MedicineNet. Genetic causes of high hematocrit levels include abnormal hemoglobin oxygen release and altered oxygen sensing, according to Lab Tests Online.
Pulmonary fibrosis causes scarring and thickening of the lungs, and this makes it harder for a patient to inhale and absorb enough oxygen, reports Lab Tests Online. The body compensates by producing a higher number of red blood cells.