AUTHOR=Smith Joe S. , Varga Anita , Schober Karsten E. 

TITLE=Comparison of Two Commercially Available Immunoassays for the Measurement of Bovine Cardiac Troponin I in Cattle With Induced Myocardial Injury

JOURNAL=Frontiers in Veterinary Science

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2020.00531

DOI=10.3389/fvets.2020.00531

ISSN=2297-1769

ABSTRACT=<p><bold>Background:</bold> Multiple cardiac troponin I (cTnI) immunoassays are commercially available. Overall, assays have not been standardized, and inter-assay differences in the detection of the analyte cardiac troponin I can be clinically relevant.</p><p><bold>Objective:</bold> To compare the diagnostic accuracy of the commercially available Abbott i-STAT®1 cTnI immunoassay (i-STAT) and the previously validated ADVIA Centaur TnI-Ultra immunoassay (Centaur) in cattle.</p><p><bold>Hypothesis:</bold> There will be significant differences in bovine serum cTnI results measured by the Centaur and i-STAT methods.</p><p><bold>Animals:</bold> Ten dairy cows with experimentally induced myocardial injury due to monensin administration. Thirty apparently healthy dairy cows with no history of monensin exposure served as controls.</p><p><bold>Methods:</bold> Blood was collected at various time points after administration of a single dose of monensin (20 to 50 mg/kg) via orogastric tube. A total of 112 blood samples were collected. Cardiac TnI concentration was analyzed with the two methods and the association between methods analyzed via linear regression. Bland-Altman analysis to evaluate agreement between methods was performed on samples divided into groups (cTnI &lt; 1.0 ng/mL and cTnI ≥ 1.0 ng/mL).</p><p><bold>Results:</bold> Analyzer results were linearly correlated with each other (<italic>R</italic><sup>2</sup> = 0.931). Samples with cTnI concentrations &lt;1.0 ng/mL had a bias of −0.13 ± 0.20 ng/mL and samples with cTnI concentrations &gt;1.0 ng/mL had a bias of −9.81 ± 13.26 ng/mL.</p><p><bold>Conclusions and clinical importance:</bold> The results of this study reveal that cTnI concentrations determined with the i-STAT are systematically lower compared to the concentrations determined by the Centaur.</p>