Design and Analytical Evaluation of Novel Cardiac Troponin Assays Targeting Multiple Forms of the Cardiac Troponin I–Cardiac Troponin T–Troponin C Complex and Fragmentation Forms

作者：Ling Li, Yuqing Liu, Ivan A. Katrukha, Litao Zhang, Xin Shu, Xu Ao, Juan Yang, Yu Wu, Yisha Jing, Hui Wang, Tongxin Ni, Karen Schulz, A. Bereznikova, Alexey G Katrukha, Fred S. Apple, Yi Zhang, Zhenlu Zhang · 发表于：Clinical Chemistry · 年份：2024 · DOI：10.1093/clinchem/hvae182 · 被引用次数：17 · 研究领域：Acute Myocardial Infarction Research、Cardiomyopathy and Myosin Studies、Cardiovascular Effects of Exercise

BACKGROUND: Current studies suggest that cardiac troponin (cTn) forms in the circulation may vary in different clinical scenarios. Our aim was to design a combination of cTn assays specific to the main cTn forms and to evaluate their analytical performance. METHODS: We developed immunoassays specific for measuring (1) long-cTnT cTnI-cTnT-TnC (ITC) ternary complex, with cTnT in long form without cleavage at the C-terminal amino acids residue 189-223, designated "long-cTnT ITC complex assay;" (2) both the long-cTnT ITC complex plus short-cTnT ITC complex, designated "hs-total ITC complex assay;" (3) the central part of cTnT of both the long-cTnT ITC complex and free cTnT, designated "hs-cTnT assay." Sex-specific 99th percentile upper reference limits (URLs) were determined. High-sensitivity performance was assessed by examining the imprecision and detectable results above limit of detection (LoD) in the healthy population. RESULTS: Both complex immunoassays exhibited excellent analytical sensitivity, precision, and specificity. The 99th percentile URLs were as follows: long-cTnT ITC complex: male 0.90 ng/L, female 0.87 ng/L; hs-total ITC complex: male 16.15 ng/L, female 10.08 ng/L; hs-cTnT: male 15.57 ng/L, female 14.28 ng/L. The total imprecision at or below the sex-specific 99th percentile URLs was <5% for all assays. The hs-total ITC complex and the hs-cTnT assays showed >50% of measurable concentrations above the LoD. However, <20% were measurable for the long-cTnT ITC comp...