Background: Cardiac troponin I (TnI) is one of the most crucial biomarkers for the management of acute coronary syndrome. However, the TnI values can vary when using commercial TnI assays from different vendors. We assessed the feasibility of TnI harmonization using plasma and serum samples.
Methods: Leftover plasma and serum samples were collected from patients and stored for further analysis (n = 200). TnI measurements were performed using 3 different analyzers. The TnI values for plasma and serum were compared, and the mathematical recalibration was performed using the mean of 3 values from each analyzer as a reference value. The number of biased cases was counted before and after recalibration.
Results: The final analysis was performed in a total of 140 plasma and serum samples, and constant and/or proportional differences for each analyzer were observed. Mathematical recalibration of the TnI values resulted in improved correlation to the reference values. The number of TnI values that were remote from the reference values decreased after recalibration. The effects were more evident for serum samples.
Conclusions: In this study, we reassured the possibility of TnI harmonization among 3 different immunoassays using plasma and serum samples. It is important to note the differences between sample types during TnI harmonization.