Potential Usefulness of Urinary Hepcidin Measurement for Iron Deficiency Anemia in Female Athletes

ABSTRACT Hepcidin is a key regulator of iron metabolism and has been proposed as a biomarker for detecting iron deficiency. This study examined serum hepcidin and non‐invasively measured urinary hepcidin in 260 female athletes to assess their potential utility in evaluating iron status. Urinary hepcidin/creatinine showed a strong correlation with serum hepcidin and was positively associated with ferritin, suggesting that it reflects underlying iron dynamics. Iron‐related measures, including hepcidin, showed expected differences across iron‐status categories, consistent with physiological changes from iron repletion to iron deficiency anemia. In diagnostic analyses, both serum hepcidin and urinary hepcidin/creatinine demonstrated good accuracy for identifying iron deficiency including iron deficiency anemia. Serum hepcidin yielded AUCs of approximately 0.85–0.90, while urinary hepcidin/creatinine showed AUCs around 0.85–0.88. Internal validation produced consistent confidence intervals, suggesting stable estimates. At the Youden‐optimal cutoff, both markers showed comparable performance, with sensitivities of 0.74–0.91, specificities of 0.73–0.92, and high negative predictive values (0.83–0.97). These cutoff values were derived from internally validated analyses and should be considered preliminary, requiring external validation before broader clinical implementation. These findings suggest that hepcidin‐based measures may assist in ruling out iron deficiency or guiding triage decisions. Because urinary hepcidin can be obtained non‐invasively and demonstrated performance similar to serum hepcidin, it may represent a practical screening option in athletic populations, although further external validation is needed.