How are history and clinical manifestations used to differentiate the various forms of anemia and polycythemia?\

The history provides information on the specific cause of anemia (inherited, nutritional, associated with a chronic disease, blood transfusion or blood loss); clinical manifestations may give clues to the specific type of anemia (megaloblastic madness associated with vitamin B12 deficiency, pica related to iron deficiency anemia, painful episodes and organ dysfunction associated with sickle cell anemia), as well as the severity, and laboratory studies are essential to correctly identify the type of anemia, because each type has specific defining characteristics (pgs. 269-283).