Polychromasia:
Chapter: 20a
Blue-gray coloration of young (anucleate) red cells when observed on a Wright-stained peripheral smear, due to the presence of residual RNA in the cytosol of the immature red cell. Polychromatic cells which are macrocytic suggest that this cell is a reticulocyte. Increased polychromasia occurs when the bone marrow releases immature RBC's into the peripheral blood in response to stress such as a hemolytic crisis.