Receiver operating characteristic curves showing the sensitivity and specificity of various tests for the diagnosis of iron deficiency (ferritin, red cell protoporphyrin, transferrin saturation, mean red cell volume, and RDW). Note that at any given level of sensitivity or specificity, serum ferritin outperforms all of the other tests shown.
RDW: red cell volume distribution width.
Data from from Guyatt GH, et al, J Gen Intern Med. 1992; 7:145.
