What term applies to an elevated red cell count of 7.8 x 10^12/L?

An elevated red cell count, such as 7.8 x 10^12/L, indicates an increase in the number of red blood cells (RBCs) present in the blood. This condition is referred to as polycythemia. Polycythemia can occur due to various reasons, including chronic hypoxia, increased erythropoietin production, or as a primary disease (such as polycythemia vera), resulting in enhanced erythropoiesis or red blood cell production.

In contrast to polycythemia, leukopenia refers to a low white blood cell count, while anemia indicates a reduction in hemoglobin or red blood cells, which would not be applicable in this case of elevated red cell count. Thrombocytosis is characterized by an increased number of platelets in the blood and is also not relevant here. Therefore, the correct term that describes an elevated red cell count is polycythemia.