TABLE 2.

Biological fluids in which the molecules of cardiospecific Tns are detected and the diagnostic role.

Biological fluid	Diagnostic role of cardiospecific Tns	Sources
Blood (whole, serum, plasma)	It is the main biological fluid used to diagnose AMI and assess the prognosis of patients suffering from non-ischemic cardiac (myocardites, Takotsubo syndrome, cardiomyopathies, etc.) and non-cardiac (sepsis, renal failure, neurogenic pathologies, etc.) pathologies that cause damage to CMC.	Lindner et al. (2014), Wu et al. (2018), Chaulin and Duplyakov (2020b), Chaulin and Duplyakov (2020c), Chuang et al. (2020), Stavroulakis and George (2020); Chauin (2021), Chaulin (2022b)
Urine	Molecules of cardiospecific Tns can be detected in this biological fluid via highly sensitive test systems. Increased troponin levels have a high prognostic value in diabetes mellitus and AH. The method of obtaining this biological fluid is non-invasive, which has a number of advantages over the use of blood. It should be noted that the possibilities of examination of HS troponins in urine are still poorly studied and have not been finally validated. Further research is needed before the introduction of this method into clinical practice	Mirzaii-Dizgah and Riahi (2013b), Odsæter et al. (2020)
Oral fluid	The levels of cardiospecific Tns in oral fluid increase in AMI and moderately correlate with serum troponin levels; therefore, further study of this area of non-invasive diagnostics is very promising	Panteghini et al. (2008), Koerbin et al. (2012), Abe et al. (2018), Bahadur et al. (2020), Bahbah et al. (2021)
Pericardial fluid and cerebrospinal fluid	Molecules of cardiospecific Tns are detected in pericardial fluid and cerebrospinal fluid via moderately sensitive and HS test systems and, according to some studies, may correlate with serum levels of cardiospecific Tns. Increased cardiospecific Tn levels in these biological fluids may reflect the degree of myocardial damage and may be used in forensic medicine to determine the cause of death. However, due to the relative paucity of such studies, further investigation of these possibilities is necessary	Ellis et al. (2001), Ziebig et al. (2003), Mishra et al. (2018), Palmiere et al. (2018), Chaulin (2021c); Hernández-Romero et al. (2021)
Amniotic fluid	Cardiospecific Tn molecules can be detected in amniotic fluid via moderately sensitive and HS-Tn immunoassays. Increased cardiospecific troponin levels may indicate chronic fetal hypoxia, abnormal development of the cardiovascular system and fetal myocardial injury, and an increased risk of fetal death during the intrauterine growth period. However, it is worth noting that such studies are few in number. Further research is needed to clarify the diagnostic capabilities of amniotic fluid	Maeda et al. (2009), Wang et al. (2011), Chen et al. (2015), González-Herrera et al. (2016)