Background Macrotroponin is an important cause of discrepancy between current high-sensitivity cardiac troponin (hs-cTn) assays, however, its clinical significance is unclear. This study examined the effects of macrotroponin and repeat testing by different hs-cTnI assays in a cohort of community patients with elevated hs-cTnI. Methods The first residual serum specimen from each patient in the community admitted to hospital with elevated hs-cTnI (Siemens hs-cTnI Centaur) was retested after immunoglobulin depletion and by 5 other hs-cTn assays. Low recovery of cTnI (<40%) following immunoglobulin depletion was considered as macrotroponin. A retrospective chart review was performed for these participants. Investigator-adjudicated diagnosis served as the reference standard. Results In our cohort of community patients with elevated troponin (n = 188), participants with macrotroponin (n = 99) often had a multifactorial or indeterminate myocardial injury (56% vs 25%) and were less likely to have acute coronary syndrome (9% vs 28%). On repeat testing of cTn on other platforms, better diagnostic performance (c-statistics) for ischemic and non-ischemic cardiac causes was observed on the Beckman Access hs-cTnI (0.74; 95% confidence interval [CI] 0.67–0.81) or the Abbott hs-cTnI Architect (0.75; CI 0.68–0.82) compared to the Siemens hs-cTnI Vista (0.62; CI 0.54–0.70; P < 0.05). This could be attributed to differences in assay reactivity for macrotroponin. Interestingly, better diagnostic performance was observed in patients without macrotroponin. Although a small number of deaths occurred (n = 16), participants with macrotroponin had better overall survival. Conclusions In the low-risk setting, the presence of macrotroponin was clinically associated with multifactorial or indeterminate causes of troponin elevation.

中文翻译：

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肌钙蛋白对心肌肌钙蛋白升高社区患者队列的影响

背景 巨肌钙蛋白是当前高敏心肌肌钙蛋白 (hs-cTn) 测定结果存在差异的重要原因，但其临床意义尚不清楚。本研究在 hs-cTnI 升高的社区患者队列中检查了 macrotroponin 和通过不同 hs-cTnI 测定重复测试的影响。方法 在免疫球蛋白耗尽后，通过 5 种其他 hs-cTn 测定重新检测社区中每名因 hs-cTnI 升高（Siemens hs-cTnI Centaur）入院的患者的第一份残留血清标本。免疫球蛋白耗尽后 cTnI 的低回收率 (<40%) 被认为是巨肌钙蛋白。对这些参与者进行了回顾性图表审查。研究者裁定的诊断作为参考标准。结果 在我们肌钙蛋白升高的社区患者队列中 (n = 188)，巨肌钙蛋白参与者 (n = 99) 通常有多因素或不确定的心肌损伤 (56% 对 25%)，并且不太可能患有急性冠状动脉综合征 (9 % 对 28%）。在其他平台上重复测试 cTn 时，在 Beckman Access hs-cTnI（0.74；95% 置信区间 [CI] 0.67–0.81）或Abbott hs-cTnI Architect (0.75; CI 0.68–0.82) 与 Siemens hs-cTnI Vista (0.62; CI 0.54–0.70; P < 0.05) 相比。这可能是由于巨钙蛋白测定反应性的差异。有趣的是，在没有巨肌钙蛋白的患者中观察到更好的诊断性能。尽管发生了少量死亡 (n = 16)，患有肌钙蛋白的参与者总体生存率更高。结论 在低风险环境中，巨肌钙蛋白的存在在临床上与肌钙蛋白升高的多因素或不确定原因相关。