What is referred to as an abnormally low RBC count?

An abnormally low red blood cell (RBC) count is known as anemia. This condition can result from various factors, including blood loss, decreased production of RBCs in the bone marrow, or destruction of RBCs. Anemia is often characterized by symptoms such as fatigue, weakness, and pallor due to insufficient oxygen transport in the body.

Hemolysis refers to the breakdown of red blood cells, which can lead to anemia but is not itself the definition of an abnormally low RBC count. Leukopenia pertains to a reduction in the number of white blood cells and is not relevant to RBC counts. Thrombocytopenia refers to a low platelet count, which impacts clotting rather than oxygen transport. Therefore, anemia is the term that specifically describes a situation where there is a deficiency in red blood cells, thereby making it the correct answer.