Validation of a Commercially Available Immunoassay for the Measurement of Bovine Cardiac Troponin I

Background: Commercially available cardiac troponin I (cTnI) assays developed for use in humans have not yet been validated for use in cattle.
Hypotheses: The ADVIA Centaur TnI-Ultra immunoassay can be used for the detection of bovine cTnI. In healthy cattle, serum cTnI is undetectable or is present only in trace amounts.
Methods: Purified bovine cTnI and cTnI-free bovine serum were used for the evaluation of assay performance including intra- and inter-assay precision, sensitivity, interference, linearity, and recovery. Effects of storage at 23, 4, ?20, and ?80 °C for 2 days, and at ?20 and ?80 °C for 7 and 14 days and repeated freeze-thaw cycles on recovery of cTnI were analyzed. Serum cTnI concentrations in 30 healthy dairy cows were determined.
Results: Intra- and inter-assay precisions (mean ± SD) were 4.48 ± 2.26 and 13.36 ± 6.59%, respectively. The assay demonstrated linearity at 0.5, 2, 15, and 30 ng/mL cTnI. Mean recovery was 100.81, 85.26, 87.72, and 114.42%, respectively. Skeletal muscle homogenate added to serum of known cTnI concentration did not alter the concentration of the analyte ( P > .05). Concentration of cTnI significantly decreased when samples were stored at 4 and 23 °C for 2 days ( P < .05). Repeated freeze-thaw cycles and storage at ?20 °C for 7 days had no significant influence on cTnI concentration ( P > .05). Serum cTnI concentration in healthy cattle was ≤0.03 ng/mL.
Conclusion and Clinical Importance: ADVIA Centaur can be used reliably for the detection of serum cTnI concentration in cattle.