{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T21:14:52Z","timestamp":1792012492457,"version":"4.4.0"},"reference-count":28,"publisher":"Oxford University Press (OUP)","issue":"8","license":[{"start":{"date-parts":[[2024,6,18]],"date-time":"2024-06-18T00:00:00Z","timestamp":1718668800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2024,8,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Long cardiac troponin T (cTnT) has been proposed to be a promising and more specific biomarker of acute myocardial infarction (AMI). As it represents a subfraction of circulating cTnT, detection of very low concentrations is a requirement. The aim of this study was to develop a novel, highly sensitive immunoassay for long cTnT.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A two-step sandwich-type immunoassay for long cTnT was developed, utilizing upconverting nanoparticles (UCNPs) as reporters. The limits of detection and quantitation were determined for the assay. Linearity and matrix effects were evaluated. Performance with clinical samples was assessed with samples from patients with non-ST elevation myocardial infarction (NSTEMI, n = 30) and end-stage renal disease (ESRD, n = 37) and compared to a previously developed time-resolved fluorescence (TRF)-based long cTnT assay and a commercial high-sensitivity cTnT assay.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The novel assay reached a 28-fold lower limit of detection (0.40\u2005ng\/L) and 14-fold lower limit of quantitation (1.79\u2005ng\/L) than the previously developed TRF long cTnT assay. Li-heparin and EDTA plasma, but not serum, were found to be suitable sample matrixes for the assay. In a receiver operating characteristics curve analysis, the troponin ratio (long\/total cTnT) determined with the novel assay showed excellent discrimination between NSTEMI and ESRD with an area under the curve of 0.986 (95% CI, 0.967\u20131.000).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>By utilizing upconversion luminescence technology, we developed a highly sensitive long cTnT assay. This novel assay can be a valuable tool for investigating the full potential of long cTnT as a biomarker for AMI.<\/jats:p>\n                    <jats:p>ClinicalTrials.gov Registration Number: NCT04465591<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/clinchem\/hvae075","type":"journal-article","created":{"date-parts":[[2024,5,29]],"date-time":"2024-05-29T10:39:12Z","timestamp":1716979152000},"page":"1037-1045","source":"Crossref","is-referenced-by-count":32,"title":["Highly Sensitive Immunoassay for Long Forms of Cardiac Troponin T Using Upconversion Luminescence"],"prefix":"10.1093","volume":"70","author":[{"given":"Selma M","family":"Salonen","sequence":"first","affiliation":[{"name":"Biotechnology Unit, Department of Life Technologies, University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tuulia J K","family":"Tuominen","sequence":"additional","affiliation":[{"name":"Biotechnology Unit, Department of Life Technologies, University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9603-6371","authenticated-orcid":false,"given":"Kirsti I S","family":"Raiko","sequence":"additional","affiliation":[{"name":"Biotechnology Unit, Department of Life Technologies, University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tuija","family":"Vasankari","sequence":"additional","affiliation":[{"name":"Heart Center, Turku University Hospital and University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rami","family":"Aalto","sequence":"additional","affiliation":[{"name":"Biotechnology Unit, Department of Life Technologies, University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tapio A","family":"Hellman","sequence":"additional","affiliation":[{"name":"Kidney Center, Turku University Hospital and University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Satu E","family":"Lahtinen","sequence":"additional","affiliation":[{"name":"Biotechnology Unit, Department of Life Technologies, University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tero","family":"Soukka","sequence":"additional","affiliation":[{"name":"Biotechnology Unit, Department of Life Technologies, University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K E Juhani","family":"Airaksinen","sequence":"additional","affiliation":[{"name":"Heart Center, Turku University Hospital and University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7886-3477","authenticated-orcid":false,"given":"Saara T","family":"Wittfooth","sequence":"additional","affiliation":[{"name":"Biotechnology Unit, Department of Life Technologies, University of Turku , Turku , Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2024,6,18]]},"reference":[{"key":"2024080108453687300_hvae075-B1","doi-asserted-by":"crossref","first-page":"2231","DOI":"10.1016\/j.jacc.2018.08.1038","article-title":"Fourth universal definition of myocardial infarction (2018)","volume":"72","author":"Thygesen","year":"2018","journal-title":"J Am Coll Cardiol"},{"key":"2024080108453687300_hvae075-B2","doi-asserted-by":"crossref","first-page":"1963","DOI":"10.3390\/jcm8111963","article-title":"Etiology of minor troponin elevations in patients with atrial fibrillation at emergency department-tropo-AF study","volume":"8","author":"Jaakkola","year":"2019","journal-title":"J Clin Med"},{"key":"2024080108453687300_hvae075-B3","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1016\/j.ijcard.2016.11.087","article-title":"High-sensitivity cardiac troponin T levels in the emergency department in patients with chest pain but no myocardial infarction","volume":"228","author":"Carlsson","year":"2017","journal-title":"Int J Cardiol"},{"key":"2024080108453687300_hvae075-B4","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.ijcard.2019.08.019","article-title":"Cardiac troponin elevations in marathon runners. 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