Which term is used to describe the condition of having an excessive number of red blood cells?

The term that describes the condition of having an excessive number of red blood cells is polycythemia. This condition results in increased blood viscosity, which can lead to various complications such as high blood pressure and an increased risk of thrombosis. Polycythemia can be classified as primary, caused by a mutation in the bone marrow that leads to an overproduction of red blood cells, or secondary, due to other factors such as chronic hypoxia or certain tumors that produce erythropoietin.

Anemia refers to a deficiency of red blood cells or hemoglobin in the blood, leading to lower oxygen transport in the body, which is the exact opposite of polycythemia. Leukocytosis indicates an increase in white blood cells, often in response to infections or inflammatory processes, and is unrelated to red blood cells. A hematoma is a localized collection of blood outside of blood vessels, usually resulting from trauma, and does not refer to the number of red blood cells in circulation.