WHAT IS RED BLOOD CELL SIZE DISTRIBUTION WIDTH (RDW) TEST?
Red blood cell volume distribution width, or RDW, is a coefficient of variation (CV) in red blood cell volume. This is derived from anisocytosis. RDW becomes abnormal earlier in iron deficiency than in any other blood cell parameters. RDW may be a useful tool in the differential diagnosis of microcytic and macrocytic anaemias. It may also be used in monitoring for improved absorption of nutrients in response to a gluten-free diet in celiac disease. It should be remembered that RDW is a CV, and it should be correlated with other erythrocytic indices for the most accurate diagnoses.