Red cell distribution width in the detection of iron deficiency in maintenance hemodialysis patients

Iron deficiency is a frequent complication in maintenance hemodialysis patients. Red cell distribution width (RDW) was recently used as an indicator in early detection of iron deficiency. One hundred and thirty nine patients maintained on hemodialysis were studied for the usefulness of RDW in detection of iron deficiency. Serum ferritin less than 30 ug/dl was defined as iron deficiency in these patients. Another 69 patients with iron deficiency not entering hemodialysis were chosen as a control group. The sensitivity of RDW elevation to detect iron deficiency in chronic hemodialysis patients was only 36.7% which was much lower than that of the control group (62.3%). However, it was still more sensitive than microcytosis in the detection of iron deficiency in chronic hemodialysis patients because none of them showed microcytosis. The specificity and positive predictive value of RDW elevation in respect to iron deficiency were 62.4% and 9.6% respectively. This study demonstrated that the use of RDW in the detection of iron deficiency in chronic hemodialysis patients was superior to mean corpuscular volume but still limited.