Red blood cell distribution width is a measure of the average size of the red blood cells. Red blood cells are important because they transport hemoglobin, which transports oxygen throughout the body. Assessment of red blood cells is typically done in a comprehensive blood count (CBC), which also measures features of white blood cells and platelets.
What does it mean if your RDW-CV (Red Cell Distribution Width is too high?
An abnormally high RDW indicates mixed populations of small and large RBCs, with younger RBCs tending to be larger. Deficiencies of vitamin B12 or folate can cause RDW to be elevated; although, a varied size distribution of red blood cells is a classic symptom of iron deficiency anemia. To further determine the cause of a high RDW level, a healthcare professional may compare the score to a patient’s mean corpuscular volume (MCV)—the average amount of space occupied by each red blood cell. If both the RDW and MCV are increased, then liver disease is a possibility.