Equis ISSN 2398-2977

Blood: troponin I

Contributor(s): Annalisa Barrelet, Ruth Morgan


  • In humans, increased serum concentrations of cardiac troponins provide a sensitive and specific marker of myocardial damage, including physical or metabolic myocardial injury, myocardial ischemia or necrosis.
  • Cardiac troponin has been studied intensively in man, and it has been found that there is a high (95%) structural agreement between mammals, making it likely that monoclonal antibodies established from the human field will be a useful in veterinary clinical pathology.
  • The cardiac troponins are thin filament-associated regulatory proteins of the heart muscle. They are crucial to the interaction between actin and myosin and occur at regular intervals along the tropomyosin molecule.
  • Cardiac troponin I (I for inhibition) is uniquely expressed in the myocardium and is a potent inhibitor of the process of actin-myosin cross-bridge formation.
  • Cardiac specificity for CTnI is 100%.


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  • Commercially available ELISA test (human).


  • Limited.
  • An increasing number of laboratories are now offering this test.



  • A high sensitivity is reported in dogs and humans but is yet to be established in horses.


  • CTnI is highly specific for myocardial pathology.

Predictive value

  • CTnI has not been associated with survival, but has been associated with the degree of cardiac damage at necropsy.

Technique (intrinsic) limitations

  • Purified equine CTnI is not available and thus absolute assay specificity cannot be achieved. However, CTnI is highly conserved among mammalian species (>95% DNA homology between human and bovine cTnI).
  • Though CTnI is specific for cardiac pathology it may be elevated in diseases in which cardiac disease is not the primary pathology, eg endotoxemia, renal disease and pulmonary embolism.
  • New test in equine clinical pathology, too few studies yet to fully validate.
  • Laboratory evaluation is currently required, however a point-of-care analyzer has undergone preliminary investigation.

Result Data

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Further Reading


Refereed papers

  • Recent references fromPubMedandVetMedResource.
  • Rossi T M et al(2014)Troponin assays in the assessment of the equine myocardium. Equine Vet J46(3), 270-275PubMed
  • Decloedt A, Verheyen T et al(2012)Acute and long-term cardiomyopathy and delayed neurotoxicity after accidental lasalocid poisoning in horses. J Vet Intern Med26(4), 1005-1011PubMed.
  • Nath L C, Anderson G A et al(2012)Serum cardiac troponin I concentrations in horses with cardiac disease. Aust Vet J90(9), 351-357PubMed.
  • Kraus M S, Jesty S A et al(2010)Measurement of plasma cardiac troponin I concentration by use of a point-of-care analyzer in clinically normal horses and horses with experimentally induced cardiac disease. Am J Vet Res71(1), 55-59PubMed.
  • Divers T J, Kraus M S et al(2009)Clinical findings and serum cardiac troponin I concentrations in horses after intragastric administration of sodium monensin. J Vet Diag Invest21(3), 338-343PubMed.
  • Phillips W, Giguère S et al(2003)Cardiac Troponin I in pastured and race-training Thoroughbred horses. J Vet Intern Med17(4), 597-599PubMed.
  • Cornelisse C J, Schott H C, Olivier N B, Mullaney T P, Koller A, Wilson D V & Derksen F J (2000)Concentration of cardiac troponin I in a horse with a ruptured aortic regurgitation jet lesion and ventricular tachycardia. JAVMA2172, 231-235PubMed.

Other sources of information

  • Schober K E, Kirbach B, Cornand C & Oechtering G (2001)Circulating Cardiac Tropinins in Small Animals.In: Proc 19th ACVIM.