Random Distribution of Width (RDW)
The RDW stands for Random Distribution of red cell Width. This value tells how consistent are the size of the red blood cells. Newly made cells (reticulocytes), B12 and folic acid deficient cells are larger than iron deficient cells. This is an electronic index that may help clarify if an anemia has multiple components. The high RDW helps determine if there is only a B12 and/or folic acid deficiency (with normal RDW showing the red cells are mostly the same size) or with concomitant iron deficiency (a high RDW due to small and large red blood cells).
Optimal Range: 13
The RDW is often increased in:
B12 and Pernicious anemia
Folic acid anemia
Iron deficiency anemia combined with other anemia
Hemolytic anemia
Transfusions
Sideroblastic anemia
en.wikipedia.org/wiki/Sider...
Alcohol abuse
Various less common and hereditary anemias
The RDW is often decreased in:
Iron deficiency anemia (blood loss, parasites, poor iron absorption, etc.)
Vitamin B6 anemia
Rheumatoid arthritis