What is "polychromasia"

n. A disorder in which there is an abnormally high number of red blood cells in the bloodstream as a result of their having been prematurely released from the bone marrow during blood formation.

Polychromasia (also known as Polychromatophilia) is a disorder where there is an abnormally high number of red blood cells found in the bloodstream as a result of being prematurely released from the bone marrow during blood formation.(Poly- refers to many, and -chromasia means color.) These cells are often shades of grayish blue. Polychromasia is usually a sign of bone marrow stress as well as immature red blood cells. 3 types are recognized, with types (1) and (2) being referred to as 'young red blood cells' and type (3) as 'old red blood cells'. Giemsa stain is used to distinguish all three types in blood smears. The young cells will generally stain gray or blue in the cytoplasm. These young red blood cells are commonly called reticulocytes. All polychromatophilic cells are reticulocytes, however, not all reticulocytes are polychromatophilic. In the old blood cells, the cytoplasm either stains a light orange or does not stain at all.