Are results of troponin I assays from different manufacturers comparable?
The results are not comparable because there is no standardization or consensus for troponin I results. The lack of comparability has been a source of confusion and irritation to clinicians.[14] Studies have shown that troponin I results may vary by a factor of 100 fold from one assay and manufacturer to another.[15] The reason for some variability in cTnI results is that cTnI is susceptible to proteolytic degradation leading to the appearance in serum of a wide diversity of peptides with different stabilities. Some cTnI epitopes remain unaltered while other epitopes are lost or altered in the degradation process.[15,16] This variability in proteolytic degradation results in different recoveries for different cTnI assays.[15,16] In addition, the antibody used by a particular manufacturer may be directed against different epitopes of troponin I, which result in assay-to-assay variation in detected levels of cTnI.[15,16] Hence, for a given patient sample, the chosen analytical method can
