RDW is a measure of anisocytosis, which is the difference in size between red blood cells. In a normalblood sample, there is some degree of anisocytosis due to the fact that younger red blood cells have a larger volume than older ones. However, an abnormally highRDW suggests a condition where red blood cells vary significantly in size, potentially indicating anemia or other blood disorders. The normal range forRDW is typically between 11% and 14%. An elevatedRDW may indicate various conditions, such asiron deficiency anemia, megaloblastic anemia, sickle cell anemia, liver disease, Renal disease, cancer (especially colorectal cancer), and other chronic diseases. Conversely, a lowRDW is usually within the normal range and does not usually indicate any significant clinical concern unless other parameters are also altered.