Anemia

Anemia

Anemia is a condition of the blood characterized by too few red blood cells to support normal physiology. Anemia (AmE) or anaemia (BrE), from the Greek (Ἀναιμία) meaning "without blood", refers to a deficiency of red blood cells (RBCs) and/or hemoglobin. Homeostasis dictates that red cell production and destruction are usually balanced in an organism. Anemias are caused by either excess red cell destruction, or underproduction of red cells. Reduction in the red blood cell content of blood can have a wide range of clinical consequences, from no noticeable symptoms for gradual-onset anemia, to cardiovascular collapse and death from rapid, profound reductions, such as seen in bleeding. Hemoglobin is the pigmented protein in blood that carries oxygen; reductions in blood hemoglobin concentrations in anemia can lead to decreased oxygen delivery to tissues.