what is normal rdw
Red cell distribution width or RDW is a parameter that measures variation in red blood cell size or red blood cell volume. A high RDW (over 14.5%) means that the red blood cells vary a lot in size. A normal RDW is 11.6 to 14.6%, but researchers from the Intermountain Medical Center Heart Institute found that patients with a RDW level greater than or equal to 12.9% had an increased risk for depression. The new study found that the higher the RDW, the greater the risk for depression for patients.
RDW-CV and RDW-SD. Red blood cell distribution width is a way for scientists to measure red blood cell volume and size. When red blood cells are larger than normal, that could indicate a problem. The reference range for RDW is as follows: 1  RDW-SD: 29-46 fL. 2  RDW-CV: 11.6 â 14.6% (for adults).