ISSN 2398-2950      

Blood biochemistry: cardiac troponin I cTnI


Joy Archer

Mark Rishniw


  • Heart disease is more common in cats than dogs and damage to heart muscle (cardiac myocytes) can be caused by many and varied other conditions. With sufficient cardiomyocyte injury or death, cardiac troponins (cTn)  are released into the systemic circulation. Of the 3 cardiac troponins, 2 are specific to cardiomyocytes and are not elevated in circulation with peripheral muscle injury - cardiac troponin I (cTnI) and cardiac troponin T (cTnT). 
  • Because of conserved homology of the TnI across species assays developed for use in humans can be used in veterinary species. Normal healthy animals have very very low or undetectable concentrations of cTnI in serum/plasma. Reference intervals for most domestic species have been established. Within 2 hours of injury this increases and can remain high with continued injury.
  • Such changes have been reported in cardiomyopathy Heart: dilated cardiomyopathy (DCM)    Heart: hypertrophic cardiomyopathy Heart: restrictive cardiomyopathy, mitral valve disease, heart damage secondary to infectious disease Endocarditis (eg Babesia, Leishmania), traumatic injury, GDV, IMHA, snake bite envenomation, heat stroke, myotoxic injury (eg monensin), myocarditis Heart: myocarditis Endomyocardial disease and in myocardial infarction (MI). However, non-cardiac diseases, especially renal disease, can also cause elevations in cTnI because of reduced clearance.
  • The most common application of cTnI assessment in domestic animals is with suspected myocardial injury. It has been shown to help prognosticate in GDV. It is less useful in identifying severity of primary heart disease such as DCM or mitral valve disease, or providing prognostic value for these diseases.
  • High sensitivity assays (that detect ultra-low concentrations of cTnI) have  been developed for use in humans, but currently have no obvious applicability in veterinary medicine.
  • cTnI concentrations might have value in predicting outcomes in dogs and cats with cardiac disease, but studies to date are limited and have little practical applicabililty for general practitioners.


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  • Commercially available automated solid-phase chemiluminescent immunometric assay for human cTnI.
  • It is a widely available standard test in veterinary laboratories.
  • It is not included in any biochemistry profiles so has to be requested separately.


  • Standard test: most veterinary diagnostic laboratories



  • Automated assays have been validated for use in dogs and cats. They have been validated in dogs with purified dog troponin (cTnI) and have been found to be highly sensitive and specific tests.
  • Troponins are highly conserved across a wide variety of species. Assays designed to measure human cTnI can be used for a variety of species.
  • Validated widely available assays: use a mouse monoclonal anti human cTnI antibody and a goat polyclonal antibody against an unique 31 amino acid extension of the cTnI- N-terminus.
  • The limit of detection of this assay varies by assay. Most 2nd and 3rd generation analyzers can detect concentrations as low as 0.01 ng/ml. New high sensitivity assays have limits of detection 10-fold lower than this. Some analyzers have limits of detection 5-fold higher than this (ie 0.2 ng/ml).
  • Comparison of data between analyzers is problematic because different analyzers use slightly different methodologies, resulting in lack of agreement. Therefore, serial analysis of cTnI in a patient should be performed on the same analyzer type.

Result Data

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Further Reading


Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Hezzell M J, Boswood A, Chang Y M, Moonarmart W, Soutar K & Elliott J (2012) The combined prognostic potential of serum sensitivity cardiac troponin I and N terminal pro-B type natriuretic peptide concentrations in dogs with degenerative mitral valve disease. J Vet Int Med 26, 302-311 PubMed.
  • Gow D J, Gow A G, Bell R, Spratt D et al (2011) Serum cardiac troponin I in dogs with  primary immune mediated haemolytic anaemia.  JSAP 52, 259-264 PubMed
  • Fonfara S, Loureiro  J, Swift S, James R, Cripps P & Dukes-McEwan J (2010) Cardiac troponin I as a marker for severity and prognosis of cardiac disease in dogs. Vet J 184, 334- 339 PubMed.
  • Ljungvall I, Hoglund K, Tidholm A, Olsen L H, Borgarelli M, Venge P, Haggstrom J (2010) Cardiac troponin I is associated with severity of myxomatous valve disease, age, and C-reactive proteins in dogs. JVIM 24, 153-159 PubMed.
  • Pelander L, Ljungvall I, Haggstrom J (2010) Myocardial cell damage in 24 dogs bitten by common Europena viper (vipera berus). Vet Rec 166, 687-690 PubMed.
  • Sharkey L C, Berzian I, Ferasin L, Tobias A H, Lulich J P, Hegstad-Davies R C (2009) Evaluation of serum cardiac troponin I concentrations in dogs with renal failure. JAVMA 234, 767-770 PubMed.
  • Porciello F, Rishniw M, HerndonW E, Birottoni F, Antognonni M T, Simpson K W (2008) Cardiac troponin I is elevated in dogs and cats with azotaemia renal failure and in dogs n on renal systemic disease. Aust Vet J  86, 390-394 PubMed.
  • Adin D B, Oyama M A, Sleeper N M, Milner R J (2006) Comparison of canine cardiac troponin I concentrations as determined by 3 analyzers. JVIM 10, 1136-1142 PubMed.
  • Burgener I A, Kovacevic A, Mauldin G N, Lombard C W (2006) Cardiac troponins as indicators of acute myocardial damage in dogs. JVIM 20, 277-288 PubMed.
  • Spratt D P, Mellanby R J, Drury N, Archer J (2005) Cardiac troponin I: evaluation of a biomarker for diagnosis of heart disease in the dog. JSAP 46, 139-145 PubMed.
  • Setling K A, Lana S E, Ogilvie G K, Olmsted A,  Mykles D L, Bright J, Richardson K L, Walton J A, Monnet E, Fettman M J (2004) Cardiac troponin I in cannie patients with lymhpoma and osteosarcoma receiving doxorubicin:comparison with clinical heart disease in a retrospective analysis. Vet Comp Oncol 2, 142-156 PubMed.
  • Archer J (2003) Cardiac biomarkers: A review. Comp Clin Path 12, 121-128.
  • Connolly D J, Cannata J, Boswood A, Aecher J, Groves E A, Neiger R (2003) Cardiac troponin I in cats with hypertrophic cardiomyopathy. J Fel Med & Surg 5, 209-216 PubMed.
  • Schober K E, Cornand C, Kirbach B, Auppele H & Oechtering G (2002) Serum cardiac troponin I and cardiac troponin T concentrations in dogs with gastric dilation- volvulus. JAVMA 221, 381-388 PubMed.


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