author(s)
Mukesh Kumar Srivastava1, Anil Ahuja, RD Velhankar, PN Panigrahi1, AP Singh, Ankita Sharma and Subhash Kacchawaha

abstract
The present study aimed to evaluate performance analysis of canine specific ET-1 sandwich enzyme-linked immunosorbent assay for the diagnosis and therapeutic evaluation of naturally occurring dilated cardiomyopathy in dogs. The estimation of endothelin-1 was performed by the commercially available canine specific quantitative sandwich ELISA kit. Recorded level of Endothelin 1(mean ± S.E.) in healthy dog was 133.33 ± 15.26 ng/dl, while in dilated cardiomyopathy affected dogs it was 243.82 ± 18.89 ng/dl. The range in healthy dogs was 48.0 - 534.34 ng/dl with undetectable level in 2.5 % dogs, while in DCM affected dogs it’s range was 4.23 - 487.49 ng/dl. Further analysis at three cut off point of i.e. 170, 180 and 190 ng/dl showed 93 %, 86 % and 72 % sensitivity and 45 %, 58 % and 63 % specificity, respectively. Cohen’s Kappa value showed fair agreement (0.348, 0.276 and 0.388 at cutoff level of ) with gold standard test at these three cut off points, while area under curve analysis showed fair diagnostic potential (0.77 and 0.72) at 170, 180 ng/dl concentration and poor (0.67) at 190 ng/dl concentration of this biomarker. Range of endothelin level seen in both groups showed huge overlapping between groups, which indicated poor discriminatory power of this biomarker for diagnosis of dilated cardiomyopathy. Although overall poor, but among three cut off levels analyzed for test performance, cut off level of 180 ng/dl has shown moderate sensitivity, specificity, false negative rate, fall-out rate and fair agreement.