Assay validation of the cardiac isoform of troponin I in double crested cormorant (Phalacrocorax auritus) plasma for diagnosis of cardiac damage

Cardiac abnormalities, initially found in Deepwater Horizon weathered MC252 crude oil exposed Double Crested Cormorants (DCCOs) upon gross necropsy, were further investigated using echocardiography. Clinical and statistically significant changes including decreased ventricular myocardial contractility and arrhythmia were elucidated by echocardiography and interpreted by boarded cardiologists as potentially life threatening. The objective of this investigation was to initiate development of an antemortem, sensitive blood screening test for cardiac damage due to oil exposure of avian species. An assay for the cardiac isoform of troponin I (cTnI) which is known to be highly cross-reactive across mammalian species was chosen and analytically validated in DCCO. This is the first time this test has been analytically validated in avian species. All plasma samples from birds assessed as healthy had trace concentrations (<0.016 ng/ml). The assays was precise and accurate revealing a coefficient of variation <3% and an R2>0.99. Diagnostic investigation revealed that the test appears to have diagnostic potential for the diagnosis of cardiomyocyte damage. Diagnostic sensitivity and specificity were 91% and 73% in this laboratory population. Due to an equivocal sample population in which health could not be proven, further investigation is needed to diagnostically validate troponin I in the assessment of oil exposure in DCCO.