Patients aged > 18 years (n = 1097), consecutively admitted to a district hospital, were included in the study. Blood samples were collected at admission and analysed with three different troponin assays. Serum was available in 92.2%, giving a study population of 1012 patients (mean age 61.6 years, 510 (50.4%) female).
ACS was diagnosed among 125 (12.4%) of the patients. Remaining patients were admitted with a broad spectrum of medical and surgical conditions. Of the total population, sc-cTnI was above the 99th percentile in 93 (9.2%), hs-cTnI was above the 99th percentile in 80 (7.9%) and hs-cTnT was above the 99th percentile in 400 (39.5%) of the patients (p < 0.001 for all differences). Hs-cTnT was stronger correlated with estimated glomerular filtration rate (r [2] = 0.13 vs r [2] = 0.06) and haemoglobin (r [2] = 0.1 vs r2 = 0.02) than with hs-cTnI, none were correlated with C-reactive protein (r [2] = 0.04 vs r [2] = 0.02).
The correlation between ln(hs-cTnT) and ln(hs-cTnI) was better in ACS patients than in non-ACS patients (r [2] = 0.79 vs r [2] = 0.47, p < 0.001).
Hs-cTnT was elevated above the 99th percentile in more than one third of the non-ACS patients, while hs-cTnI and sc-cTnI were elevated in approximately one tenth. The correlation between hs-cTnT and hs-cTnI concentrations was significantly stronger in ACS patients than in non-ACS patients.