A condition in which the number of reticulocytes in the blood increases unusually.
An increase in the proportion of immature red blood cells (reticulocytes) in the bloodstream: a sign of increased output of new red cells from the bone marrow.
An increased number of reticulocytes in the circulating blood. This condition indicates active erythropoiesis in the red bone marrow and the need for greater oxygen-carrying capacity of the blood. It occurs after hemorrhage, during acclimatization to high altitude, during any pulmonary disorder that induces hypoxia, and in all types of anemia.