Urinary hepcidin levels in 2 controls and the proband, before and after ingestion of 80 mg iron as ferrous sulfate. Synthetic hepcidin standards (20, 50, and 100 ng) and urinary extracts equivalent to 0.5 mg creatinine were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting with rabbit anti-human hepcidin antibody. 0 = urine collected before iron ingestion; Fe = urine collected 24 hours after iron ingestion. Measures of urinary hepcidin, serum transferrin saturation, and serum ferritin are given for each subject at the indicated test times.