Evaluation of a commercial liquid-chromatography high-resolution mass-spectrometry method for the determination of hepcidin-25

Introduction: Reliable determination of hepcidin-25, a key regulator of iron metabolism, is important. This study aimed at evaluating the performance of the Hepcidin-25 Liquid Chromatography-Tandem Mass-Spectrometry (LC-MS/MS) Kit (Immundiagnostik AG, Bensheim, Germany) for quantification of the hepcidin-25 protein. Materials and methods: Precision, accuracy, linearity, and preanalytical requirements of the liquid-chromatography high-resolution massspectrometry (LC-HR-MS) method were evaluated. The imprecision and bias acceptance criteria were defined <= 15%. We investigated sample stability at room temperature (RT) and after repeated freeze and thaw cycles. Additionally, we assessed serum hepcidin-25 concentrations of 165 healthy adults referred for a medical check-up. Results: The hepcidin-25 LC-MS/MS assay was linear over the concentration range of 3 - 200 ng/mL. Within-and between-run precision ranged between 1.9 - 8.6% and 5.1 - 12.4%, respectively. The mean bias of the low and high control material was -2 .7% and 2.1%, respectively. At RT, serum samples were stable for 3 h (mean bias + 0.3%). After two and three freeze and thaw cycles, hepcidin-25 concentrations showed a bias of + 8.0 and + 20%, respectively. Of 165 healthy adults, 109 females had a significantly lower median of 8.42 (range: 1.00 - 60.10) ng/mL compared to 56 males with 15.76 (range: 1.50 -60.50) ng/mL (P = 0.002). Conclusions: The hepcidin-25 LC-MS/MS kit shows a broad analytical range and meets the imprecision and bias acceptance criteria of <= 15%. Serum samples can be stored at RT for 3 h and resist up to two freeze and thaw cycles.