Concentration of high-sensitivity cardiac troponin I in the oral fluid in patients with acute myocardial infarction: a pilot study

Aim . To assess the potential of using oral fluid as a non-invasive diagnostic material in patients with myocardial infarction (MI). Material and methods . The pilot, single-center, prospective study included 47 patients with documented MI, among whom there were 33 men (71%) and 14 women (29%) (mean age, 61,72±12,09 years). All patients successfully treated with reperfusion therapy. The control group consisted of 15 people in whom MI was not confirmed. The concentration of high-sensitivity cardiac tro -ponin I ( hs-cTnI) in blood and oral fluid was determined using chemilumines -cence enzyme immunoassay (CLEIA) on a PATHFAST analyzer (LSI Medience Corporation). Medium sensitivity cardiac troponin I (ms-cTnI) was determined in blood using an Access 2 immunoassay system analyzer (Beckman Coulter, USA). Levels of total bilirubin, creatinine, glucose, rheumatoid factor, alkaline phosphatase and other biochemical parameters were determined on a Furuno CA-400 analyzer (Japan). Results . The levels of hs-cTnI in patients with MI were significantly higher than in healthy patients both in blood (8,73±1,17 ng/ml vs 0,012±0,03 ng/ml, p<0,001) and oral fluid (0,41±0,11 ng/ml vs 0,004±0,001 ng/ml, p<0,001). In patients with-AMI, there was a moderate correlation between the concentration of hs-cTnI in the serum and the oral fluid (r=0,319; p<0,05). The serum level of hs-cTnI in patients with Q-wave (n=33) and non-Q-wave (n=14) MI was 10,11±1,53 ng/ ml vs 5,48±1,29 ng/ml, respectively (p=0,025). The oral fluid concentration of hs-cTnI in patients with W-wave (n=33) and non-Q-wave (n=14) MI was 0,42±0,14 ng/ml vs 0,40±0,16 ng/ml, respectively (p=0,925). The serum level of hs-cTnI in anterior MI (n=19) was 8,92±2,06 ng/ml vs 8,91±1,81 ng/ml in posterior one (n=23) (p=0,997). The concentration of hs-cTnI in the oral fluid was 0,21±0,06 ng/ml vs 0,57±0,21 ng/ml, respectively (p=0,107). The oral fluid concentrations of hs-TnI in patients with MI using conventional plastic tubes (n=26) and special Sarstedt microtubes (n=21) were 0,56±0,19 ng/ml and 0,22±0,10 ng/ml, respectively (p=0,12). Conclusion. This pilot study has proven the possibility of detecting hs-cTnI in the oral fluid of patients with MI. There was a moderate correlation between the level of hs-cTnI in blood serum and oral fluid. Further research is needed to determine the hs-cTnI reference values in the oral fluid of patients with MI.