## 3 Results  
[PERSON]'s test showed that there was a significant association between cTnI and cTnT in NSTEMI (r = 0.70) and Type 2 (r = 0.75) groups with a \(p\)-value below the 0.05 statistical significance level. No correlation was found in the control group (r = -0.06). The correlation was not calculated for the STEMI group since the number of patients was too low. Mean values and ratios relative to respective cut-offs are presented in Table 2. For the STEMI group, the data are not presented. Nevertheless, the calculation was performed as additional information. The means and ratios for cTnI and cTnT were 9998 ng/L (ratio 172) and 286 ng/L (ratio 17.0) for males. For females means and ratios for cTnI and cTnT were 6115 ng/L (ratio 153) and 176 ng/L (ratio 19.5), respectively. In the next step, we looked into the group of patients in whose value of cTnI and cTnT did not match as expected. We found out that the elevation of cTnI and cTnT matched in 82% of cases, while in 18% of cases, only cTnI was elevated and cTnT was not. For these unmatching cases we obtained additional information on the medical history and any comorbidities. The additional diagnoses were classified into those with elevated cTnI due to coronary causes (73%) and those with elevated cTnI of non-coron \begin{table}
\begin{tabular}{l c c} \hline  & **cTnI in Serum** & **cTnT in Serum** & **cTnT in Serum** \\  & **(ADVIA Centaur XP)** & **(Cobas e411)** \\ \hline Intra-assay variation [\%] & 1.5–6.1 & 0.8–7.1 \\ (repeatability) & & & \\ \hline Inter-assay variation [\%] & & & \\ (intermediate precision) & & & \\ \hline Limit of detection [ng/L] & & 2.21 & 2.54 \\ \hline Limit of quantification [ng/L] & & 2.50 (at CV = 20\%) & 7.45 (at CV = 10\%) \\ \hline Cut-off [ng/L] & F & 39.6 & F & 9.0 \\ (99 th percentile) & M & 58.0 & M & 16.8 \\  & (population mean 46.5) & (population mean 14.0) \\ \hline \end{tabular}
\end{table} 
Table 1: Specifications of methods used for the measurement of troponin. \begin{table}
\begin{tabular}{l l c c c c c} \hline  & **Gender** & **n** & \multicolumn{2}{c}{**cTnI**} & \multicolumn{2}{c}{**cTnT**} \\ \cline{2-7}  & & & **Mean** & **Ratio** & **Mean** & **Ratio** \\  & & & **(ng/L)** & **Ratio** & **(ng/L)** & **Ratio** \\ \hline Control & M & 14 & 38.9 & 0.67 & 50.7 & 3.02 \\  & F & 7 & 57.4 & 1.44 & 41.5 & 4.61 \\ \hline NSTEMI & M & 31 & 1423 & 24.6 & 220.1 & 13.1 \\  & F & 12 & 2133 & 53.3 & 187.0 & 20.8 \\ \hline Type 2 & M & 26 & 733.7 & 12.7 & 113.7 & 6.73 \\  & F & 22 & 1024 & 25.6 & 171.1 & 19.0 \\ \hline \end{tabular}
\end{table} 
Table 2: Mean values of cTnI and cTnT concentrations and their ratios relative to respective cut-offs (multiples of cut-off). For cTnI, the following cut-offs were used: 40 ng/L for females and 58 ng/L for males. For cTnT, the cut-offs were 9.0 ng/L for females and 16.9 ng/L for males. in this group of patients included Myocardial infarction with non-obstructive coronary arteries (MINOCA), coronary artery disease, tachycardia, cardiogenic syncope, heart failure, endocarditis, aortic stenosis, critical lower limb ischemia, bradycardia, ischemic heart disease, subacute STEMI (Table 3). Patients with known coronary disease and patients referred for coronary angiography were also included in this group. In all these conditions, the release of troponin from myocytes is due to cardiac injury, either due to reduced blood flow to the heart, inflammation, or cardiac ischemia. The subgroups were too small for statistical analysis. Nevertheless, as a preliminary information means and medians of cTnI levels were calculated. In the heart-related group the mean concentration of cTnI was 316.7 ng/L (median 190 ng/L), while in the non-heart-related group the mean concentration of cTnI was 225.9 ng/L (median 152.5 ng/L).