Detecting damage to the heart muscle using straightforward blood tests that measure cardiac troponin I (cTnI) and troponin T (cTnT) is routine in human medicine. Such tests play important roles in diagnosing heart disease rapidly and instituting appropriate therapy.

Horses also suffer from various heart conditions—such as valvular insufficiency, endocarditis, and atypical myopathy—and could reap the benefits of such testing, but there is little data supporting human cardiac blood tests’ use in horses.

“Troponin is a complex of three proteins–cardiac troponin I, C, and T–that plays an integral role in cardiac muscle contraction,” explained Gunther van Loon, DVM, PhD, from the Ghent University’s Department of Large Animal Internal Medicine, in Belgium. “When the heart is damaged, those proteins are released from the muscle and circulate in the blood where they can be measured.”

Troponin proteins are very similar between species, meaning veterinarians could theoretically use human troponin tests in horses because the proteins “look” the same. While several commercially available cTnI tests are available for use in horses, the different assays yield different results. In contrast, there is only one assay for cTnT, which could be a good alternative to cTnI testing