Serum albumin, creatine kinase (CK), ferritin, iron, and total iron-binding capacity (TIBC) were analyzed using a JCA-BM8060 automated analyzer (Japan Electron Optics Laboratory Ltd., Tokyo, Japan). Hematologic parameters, including white blood cell, red blood cell, hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume, mean corpuscular hemoglobin (MCH), MCH concentration, and platelet (PLT), were analyzed using a Sysmex XE 2100 automated hematology analyzer (Sysmex Corporation, Kobe, Japan). A commercial laboratory service, Hoken Kagaku Inc. (Yokohama, Japan), conducted the analyses and provided reference ranges of healthy Japanese male adults.
Serum hepcidin was analyzed using a commercially available enzyme immunoassay kit (Quantikine ELISA Human Hepcidin Immunoassay, R&D Systems, Minneapolis, MN, USA). The sample range was provided by the manufacturer.
TSAT was calculated as serum iron/TIBC. The reference range was obtained from the MDS Manual Professional Edition.