Troponin
Troponin is a protein of muscle, blood levels of which have become important in diagnosis. "Its function is to serve as the calcium-binding component in the troponin-tropomyosin B-actin-myosin complex by conferring calcium sensitivity to the cross-linked actin and myosin filaments.[1]
"Cardiac troponins are regulatory proteins of the thin actin filaments of the cardiac muscle. Troponin T and troponin I are highly sensitive and specific markers of myocardial injury."[2] The level of troponin in the blood of normal individuals may be less than 0.0064 microg/l according to a study of a highly sensitive assay.[3] However, even this cutoff level does not perfectly discriminate normal individuals from patients having acute coronary syndrome.
Troponin levels have become an important diagnostic tool in assessing acute coronary syndrome, but it is dangerous to assume that ACS is the only reason they may be elevated. They supplement, but do not replace, the electrocardiogram, history, and physical examination.
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Test accuracy
Accuracy for detecting myocardial infarction is improved by using a high sensitivity assay.[4]
The highly sensitive assay can detect elevations in patients with chronic stable coronary heart disease.[5] These patients are at increased risk of adverse events.[5]
References
- ↑ Anonymous (2024), Troponin (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Ammann P et al.' (2004 May 1), "Raised cardiac troponins: Causes extend beyond acute coronary syndromes", BMJ 328 (7447): 1028–1029., DOI:10.1136/bmj.328.7447.1028
- ↑ Venge P, Johnston N, Lindahl B, James S (2009). "Normal plasma levels of cardiac troponin I measured by the high-sensitivity cardiac troponin I access prototype assay and the impact on the diagnosis of myocardial ischemia.". J Am Coll Cardiol 54 (13): 1165-72. DOI:10.1016/j.jacc.2009.05.051. PMID 19761938. Research Blogging.
- ↑ Reichlin T, Hochholzer W, Bassetti S, Steuer S, Stelzig C, Hartwiger S et al. (2009). "Early diagnosis of myocardial infarction with sensitive cardiac troponin assays.". N Engl J Med 361 (9): 858-67. DOI:10.1056/NEJMoa0900428. PMID 19710484. Research Blogging.
- ↑ 5.0 5.1 Omland T, de Lemos JA, Sabatine MS, Christophi CA, Rice MM, Jablonski KA et al. (2009). "A Sensitive Cardiac Troponin T Assay in Stable Coronary Artery Disease.". N Engl J Med. DOI:10.1056/NEJMoa0805299. PMID 19940289. Research Blogging.