マクロトロポニンが免疫測定法トロポニンアッセイに及ぼす臨床的影響：クロス分析ケース評価

High-sensitivity cardiac troponin assays are susceptible to analytical interferences, including macrotroponin, an immunoglobulin-bound complex that may cause persistent, non-dynamic, and assay-dependent elevations. This paper describes the case of a 74-year-old woman with hypertension who presented with intermittent mild chest discomfort and exertional dyspnea and exhibited persistently elevated but stable cardiac troponin I concentrations over several months, in the absence of clinical, electrocardiographic, or imaging evidence of myocardial injury. Orthogonal testing revealed discordant results across different assay platforms, and polyethylene-glycol (PEG) precipitation resulted in a substantial signal reduction, confirming macrotroponin as the source of assay-dependent analytical interference. Recognizing this phenomenon is crucial to avoid misdiagnosis, unnecessary diagnostic procedures and inappropriate management in patients with isolated troponin elevation. In conclusion, this report provides evidence-based recommendations on the optimal diagnostic strategies and laboratory approaches to adopt in cases of suspected macrotroponin-mediated interference in high-sensitivity cardiac troponin assays.