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 from PubMed and VetMedResource.
  • Rossi T M et al (2014) Troponin assays in the assessment of the equine myocardium. Equine Vet J 46 (3), 270-275 PubMed
  • Decloedt A, Verheyen T et al (2012) Acute and long-term cardiomyopathy and delayed neurotoxicity after accidental lasalocid poisoning in horses. J Vet Intern Med 26 (4), 1005-1011 PubMed.
  • Nath L C, Anderson G A et al (2012) Serum cardiac troponin I concentrations in horses with cardiac disease. Aust Vet J 90 (9), 351-357 PubMed.
  • 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 Res 71 (1), 55-59 PubMed.
  • 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 Invest 21 (3), 338-343 PubMed.
  • Phillips W, Giguère S et al (2003) Cardiac Troponin I in pastured and race-training Thoroughbred horses.  J Vet Intern Med 17 (4), 597-599 PubMed.
  • Cornelisse C J, Schott H C, Olivier N B et al (2000) Concentration of cardiac troponin I in a horse with a ruptured aortic regurgitation jet lesion and ventricular tachycardia.  JAVMA 217 (2), 231-235 PubMed.

Other sources of information

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