Validation of an immunoassay for measurement of canine cardiac troponin-I.
Cardiac troponin-I (cTnI) is a sensitive and specific circulating marker of cardiac injury. The amind acid sequence of canine troponin-I suggests that immunoassays designed for humans may be able to quantify canine cTnI. We sought to validate the AccuTnItrade mark system for use in the canine species. Samples of purified canine free cTnI, cardiac troponin I-C (cTnI-C), and cardiac troponin I-T-C (cTnI-T-C) were used to assess the performance characteristics of the assay. Intra-assay precision was 4.2 +/- 3.0% and inter-assay precision was 4.5 +/- 2.7%. The assay demonstrated linearity of serial dilutions from 0.015 to 30 ng/ml for all forms of cTnI (R, 0.998 to 0.999). Mean recovery of cTnI was 92.5 +/- 10.5%, of cTnI-C was 147.2 +/- 19.8%, and of cTnI-T-C was 97.3 +/- 23.5%. Specificity of the assay for the cardiac form of troponin-I was confirmed using samples spiked with canine skeletal muscle troponin-I. The AccuTnItrade mark assay was evaluated in 27 canine patients. Dogs with heart disease (cardiomyopathy or severe mitral valve disease, n = 13) had a higher mean cTnI concentration than controls (disease cTnI = 0.68 ng/ml, range 0.03-5.47 ng/ml vs. control cTnI = 0.03 ng/ml, range 0.01-0.08 ng/ml; P = 0.0003). The AccuTnItrade mark assay possesses sufficient test performance for use with canine plasma and can distinguish a cohort of dogs with heart disease from a cohort of healthy controls. The results of this study suggest that further investigations into the clinical use of the AccuTnItrade mark assay for the diagnosis of canine heart disease are warranted.
Oyama
Mark A
MA
Department of Veterinary Clinical Medicine.
Solter
Philip F
PF