has part has part characteristic of inheres in has modifier hemoglobin erythrocyte Abnormal erythrocyte morphology Anemia HP:0001903 Decreased haemoglobin HP:0005509 Low number of red blood cells or haemoglobin HP:0001926 Anemia is not a specific entity but can result from many underlying pathologic processes. The three main causes of anemia are blood loss, decreased or faulty red blood cell production, and increased destruction of red blood cells. Various classifications are in clinical use including a classification according to the mean corpuscular volume (MCV) of the erythrocytes: microcytic, macrocytic, or normocytic. Anemias can also be classified according to variations in cell size and shape, as reflected by the red-cell distribution width (RDW). Additionally, anemias can be classified into those of inadequate production and hemolytic anemias. SNOMEDCT_US:165397008 UMLS:C0162119 Anaemia Decreased hemoglobin SNOMEDCT_US:271737000 Low number of red blood cells or hemoglobin UMLS:C0002871 HP:0003136 A reduction in erythrocytes volume or hemoglobin concentration. abnormal decreased volume decreased amount