Stability of Cardiac Troponin-I in Whole Blood and Plasma in Patients with Acute Myocardial Infarction

Introduction: In this study, we aimed to investigate the short-term stability and variability of cardiac troponin T (cTnI) in ethylenediamine tetraacetic acid (EDTA) whole blood, heparinized whole blood, and EDTA plasma. Methods: Thirteen patients with myocardial infarction were included. Venous blood samples (24 mL) from all patients were collected into vacuum tubes with EDTA and heparin (Becton Dickinson-USA), and analyses were performed on four different groups (one group for repeatability and three groups for stability). Results: There was no statistically significant difference in cTnI concentrations at baseline, 2, 4, 6, 12, 24, and 48 hours between the heparinized whole blood, EDTA whole blood, and EDTA plasma groups (group 2) (p>0.05). In the heparinized whole blood and EDTA plasma groups, there was a statistically significant difference between cTnI concentrations at baseline, 2, 4, 6, 12, 24, and 48 hours. In the EDTA whole blood group, there was no statistically significant difference between any time points. Conclusion: The interclass and intraclass correlation coefficients of the EDTA whole blood group were sufficiently high, which indicates better stability. EDTA whole blood samples are preferable for cTnI measurement because they are stable for 48 hours. EDTA-containing tubes are easy to find in clinical laboratories and do not need to be centrifuged, which saves time and effort.