Final answer:
polycythemia. An abnormal excess of erythrocytes is called polycythemia. Polycythemia can occur transiently in dehydrated individuals and is also associated with a bone marrow disease called polycythemia vera.
Step-by-step explanation:
An abnormal excess of erythrocytes is called polycythemia. Polycythemia is detected through an elevated hematocrit, which is the percentage of red blood cells in the blood. It can occur transiently in dehydrated individuals due to inadequate water intake or excessive water losses. Polycythemia can also be caused by a bone marrow disease called polycythemia vera, which results in excessive production of immature red blood cells.