Final answer:
An elevated RBC count is called polycythemia and is detected in a patient's elevated hematocrit. It can occur transiently in a person who is dehydrated or as a result of certain bone marrow diseases. Polycythemia can dangerously elevate the viscosity of blood, making it more difficult for the heart to pump blood throughout the body.
Step-by-step explanation:
In contrast to anemia, an elevated RBC count is called polycythemia and is detected in a patient's elevated hematocrit. It can occur transiently in a person who is dehydrated; when water intake is inadequate or water losses are excessive, the plasma volume falls. As a result, the hematocrit rises. For reasons mentioned earlier, a mild form of polycythemia is chronic but normal in people living at high altitudes. Some elite athletes train at high elevations specifically to induce this phenomenon. Finally, a type of bone marrow disease called polycythemia vera (from the Greek vera = “true”) causes an excessive production of immature erythrocytes. Polycythemia vera can dangerously elevate the viscosity of blood, raising blood pressure and making it more difficult for the heart to pump blood throughout the body. It is a relatively rare disease that occurs more often in men than women, and is more likely to be present in elderly patients those over 60 years of age.