Elevated levels of cardiac troponin I or T (cTnI, cTnT) in general have immediate clinical consequences including invasive cardiac imaging and rhythm monitoring. Macro-troponin is a complex of antitroponin autoantibodies and cTnI or cTnT and may result in falsely elevated values. In athletes, a reliable exclusion of cardiac disease is crucial to allow for intensive exercise. The prevalence and causes of falsely elevated cTn in professional athletes after SARS-CoV-2 infection are unknown.

These are preliminary results of an observational study including 35 professional athletes (16 -75 years old, median 24 years; 19 females, 16 males) who had post-Covid-19 check-ups at their practicing sports physician mostly in the year 2022 (6 athletes in 2023). One female athlete did not have a proven SARS-CoV-2 infection but vaccination. Divergences in high sensitivity (hs) cTn concentrations were investigated according to the sex-specific cut-off values of 4 different assays (hs-cTnI: Alinity/Abbott Diagnostics, Atellica/Siemens Healthineers, Access/Beckman Coulter and hs-cTnT: Cobas/Roche Diagnostics). All athletes were advised to stop training 48h before routine blood drawing and if required underwent electrocardiography (ECG), echocardiography and magnetic resonance imaging to exclude myocardial involvement, particularly when suspicious symptoms were present. Athletes with divergent hs-cTn assay results were further analyzed for the presence of macro-troponin using the reference method sucrose gradient ultracentrifugation.

The two main professional sports were cycling (mountain biking or road biking) and soccer, further sports comprised curling, swimming, running including marathon, floorball, cross-country skiing or rhythmic gymnastics. Athletes mostly suffered from postviral exhaustion, mild infectious symptoms like headache, sore throat, dry cough, subfebrile temperature, or sniffles or had atypical thoracic pain. There were two males with known secondary diagnoses, one 25 years old with diabetes mellitus type 1 and one 75 years old with atherosclerosis and hypercholesterolemia. Eighteen (18/35) athletes had hs-cTn concentrations within the sex-specific cut-off values in all assays and did not undergo further investigation for macro-troponin by sucrose gradient ultracentrifugation. However, in 17 athletes (17/35) hs-cTn was increased in at least one assay method which was mostly a hs-cTnI method (for 2/17 all assays elevated). The sucrose-gradient ultracentrifugation method proved macro-troponin in 15/17 with original hs-cTn values for Abbott Alinity: 5 - 170 ng/L; Siemens Atellica: 9.6 - 376 ng/L; Beckman Access: 0.5 - 55 ng/L and Roche Cobas 4 - 77 ng/L. However, 2/17 had the free troponin form, one with only a minor hs-cTnT increase above the sex-specific cut-off and the other with increased values in all hs-cTn assays but normal values in a 2- and 4-days control follow-up measurement. Notably, there were no ECG or cardiac imaging findings including echocardiography or cardiac magnetic resonance imaging suggestive of myocarditis in the investigated athletes.

After SARS-CoV-2 infection, cTn might be increased in athletes without a correlate in ECG or imaging reports. This should prompt physicians to consider an assay interference by macro-troponin, particularly if a second troponin method such as hs-cTnT remains normal.