The Use of Red Cell Distribution Width in the Detection of Iron Deficiency in Chronic Hemodialysis Patients

Forty patients on maintenance hemodialysis were studied to determine the usefulness of the red blood cell distribution width (RDW) in screening these patients for iron deficiency. Serum ferritin was used as the indicator of body iron stores. The sensitivity of RDW elevation in determining the likelihood of iron store depletion was 89%; and the negative predictive value of a normal RDW was 93%. The specificity of RDW elevation for iron deficiency was only 45%, and the positive predictive value was 32%. This study has confirmed the usefulness of the RDW as a screening test for iron deficiency in chronic hemodialysis patients. However, the low specificity and positive predictive value of the test also suggests the need for further studies when there is an unexplained elevation of the RDW.