High incidence of macrotroponin I with a high-sensitivity troponin I assay
High incidence of macrotroponin I with a high-sensitivity troponin I assay
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DOI：
10.1515/cclm-2015-1276
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发表时间：
2016-11-01
影响因子：
6.8
通讯作者：
Marshall, George A.
中科院分区：
文献类型：
--
作者：
Warner, Janet V.;Marshall, George A.
背景：心肌肌钙蛋白是心肌损伤的首选生物标志物。高灵敏度的肌钙蛋白检测方法能够以极高的精确度测量非常低的肌钙蛋白水平。在引入了一种高灵敏度的肌钙蛋白I检测方法后，实验室开始收到临床医生对升高的肌钙蛋白I结果不一致的询问。方法：常规临床标本用架构师高敏肌钙蛋白I(HsTnI)和VITROS肌钙蛋白I Es分析(VitrosTnI)进行检测。根据Architect法升高而不是VITROS法升高的结果(组1)或两种方法升高但Architect法升高的结果不成比例地高于Architect法的结果(组2)，在重新离心、多次稀释、与异嗜性封闭试剂孵育、聚乙二醇沉淀法和蛋白A/G/L处理后重新分析hsTnI。结果：在5%的hsTnI升高患者中，检测到一种含有免疫反应性肌钙蛋白I和免疫球蛋白的高分子量复合体。与VitrosTnI相比，同时存在巨肌钙蛋白和心肌损伤的患者hsTnI升高更高且持续时间更长，且GFC上同时出现巨肌钙蛋白和游离肌钙蛋白I-C复合体的峰值。结论：循环巨肌钙蛋白I(MacTnI)可引起hsTnI升高，这可能具有临床误导性。这项研究中涉及的化验可能不是唯一受大肌钙蛋白影响的化验。对于实验室和临床医生来说，重要的是要意识到并制定程序来识别和管理由于巨肌钙蛋白导致结果升高的标本。
Background: Cardiac troponin is the preferred biomarker of myocardial injury. High-sensitivity troponin assays allow measurement of very low levels of troponin with excellent precision. After the introduction of a high-sensitivity troponin I assay the laboratory began to receive enquiries from clinicians about clinically discordant elevated troponin I results. This led to a systematic investigation and characterisation of the cause.Methods: Routine clinical samples were measured by the Architect High Sensitive Troponin-I (hsTnI) and the VITROS Troponin I ES assays (VitrosTnI). Results that were elevated according to the Architect but not the VITROS assay (Group 1) or results elevated by both assays but disproportionately higher on the Architect (Group 2) were re-analysed for hsTnI after re-centrifugation, multiple dilutions, incubation with heterophilic blocking reagents, polyethylene glycol (PEG) precipitation, and Protein A/G/L treatment. Sephacryl S-300 HR gel filtration chromatography (GFC) was performed on selected specimens.Results: A high molecular weight complex containing immunoreactive troponin I and immunoglobulin (macrotroponin I) was identified in 5% of patients with elevated hsTnI. Patients with both macrotroponin and myocardial injury had higher and longer elevation of hsTnI compared with VitrosTnI with peaks of both macrotroponin and free troponin I-C complex on GFC.Conclusions: Circulating macrotroponin I (macroTnI) causes elevated hsTnI results with the Architect High Sensitive Troponin-I assay with the potential to be clinically misleading. The assay involved in this investigation may not be the only assay affected by macrotroponin. It is important for laboratories and clinicians to be aware of and develop processes to identify and manage specimens with elevated results due to macrotroponin.