False-positive cardiac troponin I values due to macrotroponin in healthy athletes after COVID-19

What is it about?

Purpose of the study: Troponins are substances released into the blood during heart attack. Doctors test for them – especially forms called I and T – to check for heart damage. But troponin levels can also rise for other reasons, for example in heart muscle inflammation (myocarditis). When this happens, doctors order detailed procedures like heart scans, catheterization, or even take a heart tissue sample. Sometimes, high troponin isn't caused by heart damage; it may be due to something harmless called macrotroponin, which forms when troponin sticks to natural antibodies possibly present after an infection like COVID-19. In athletes, ensuring heart health after infections like COVID-19 is important, but it’s unclear how often macrotroponin causes such false-positive troponin results and leads to unnecessary, possibly risky procedures. What we did: We studied 35 healthy athletes (ages 16–75) who had check-ups after recovering from COVID-19 between 2022 and 2023. Their troponin levels were measured using four different lab tests. If the test results didn’t match, we looked for signs of macrotroponin using three specialized methods. What we found: Seventeen athletes had normal results. The other 18 (51%) had elevated troponin levels, mainly the I form. However, none of the athletes showed signs of heart problems on imaging or other tests. In 16 of these 18, the elevated levels were caused by macrotroponin, and also natural antibodies against troponin were found. Conclusion: False-positive troponin results were common in athletes after COVID-19. Being aware of macrotroponin can help avoid unnecessary testing, stress, and healthcare costs.

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