Department of Laboratory Medicine, Drammen Hospital, Vestre Viken Hospital Trust, Norway.
Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Norway.
Ann Clin Biochem. 2023 Sep;60(5):298-305. doi: 10.1177/00045632231159529. Epub 2023 Mar 3.
The iron-regulatory hormone hepcidin is a promising biomarker to differentiate anaemia of inflammation from iron deficiency. Plasma hepcidin concentrations increase substantially during inflammation, and the amount of smaller, non-biologically active isoforms of hepcidin increase in inflammatory conditions. These smaller isoforms are measured in some, but not all analytical methods. Thus, we evaluated the comparability of two analytical methods with different isoform selectivity during and after acute-phase pneumonia as a highly inflammatory model disease.
Blood samples from a cohort of 267 hospitalized community-acquired pneumonia patients collected at admission and a 6-week follow-up were analysed. Hepcidin was measured in plasma by an immunoassay, which recognizes all hepcidin isoforms, and a liquid chromatography tandem mass spectrometry (LC-MS/MS), which selectively measures the bioactive hepcidin-25. Additionally, a subset of serum samples was analysed by LC-MS/MS.
Hepcidin measurements by immunoassay were higher compared with LC-MS/MS. The relative mean difference of hepcidin plasma concentrations between the two analytical methods was larger in admission samples than in follow-up samples (admission samples <200 ng/mL: 37%, admission samples >200 ng/mL: 78%, follow-up samples >10 ng/mL: 22%). During acute-phase pneumonia, serum concentrations were on average 22% lower than plasma concentrations when measured by LC-MS/MS.
Immunoassay measured higher hepcidin concentrations compared with LC-MS/MS, with more pronounced differences in high-concentration samples during acute-phase pneumonia. These findings should be considered in local method validations and in future harmonization and standardization optimization of hepcidin measurements.
铁调节激素铁调素是区分炎症性贫血和缺铁性贫血的有前途的生物标志物。铁调素在炎症期间会大量增加，而在炎症条件下，铁调素的小的、无生物学活性的同工型的量会增加。这些较小的同工型在一些但不是所有的分析方法中都有测量。因此，我们评估了两种分析方法在急性肺炎期间和之后的可比性，急性肺炎是一种高度炎症性模型疾病。
对 267 名住院社区获得性肺炎患者的队列在入院时和 6 周随访时采集的血液样本进行了分析。铁调素通过免疫测定法（可识别所有铁调素同工型）和液相色谱串联质谱法（LC-MS/MS）（选择性测量生物活性的铁调素-25）在血浆中进行测量。此外，还通过 LC-MS/MS 分析了一部分血清样本。
免疫测定法测量的铁调素值高于 LC-MS/MS。两种分析方法之间的铁调素血浆浓度的相对平均差异在入院样本中大于随访样本（<200ng/mL 的入院样本：37%，>200ng/mL 的入院样本：78%，>10ng/mL 的随访样本：22%）。在急性肺炎期间，当通过 LC-MS/MS 测量时，血清浓度平均比血浆浓度低 22%。
免疫测定法测量的铁调素浓度高于 LC-MS/MS，在急性肺炎期间高浓度样本中差异更为明显。在局部方法验证以及未来的铁调素测量的协调和标准化优化中，应考虑这些发现。
