# False-positive troponin in a professional cyclist: a case report on avoiding misdiagnosis and unnecessary restrictions

## TL;DR

A professional cyclist had falsely high troponin levels due to macrotroponin complexes, not heart damage, highlighting the need for accurate diagnosis to avoid unnecessary restrictions.

## Contribution

Highlights macrotroponin as an underrecognized cause of elevated troponin in athletes and proposes a simple diagnostic method to avoid misdiagnosis.

## Key findings

- Elevated troponin I but normal troponin T suggested macrotroponin complexes in the athlete.
- PEG precipitation confirmed the presence of macrotroponin complexes, allowing safe return to sports.
- Exercise-induced troponin release may increase macrotroponin formation in athletes.

## Abstract

Myocarditis can cause sudden cardiac death in athletes, and in the presence of clinical symptoms and elevated troponins, exercise restriction is recommended. However, macrotroponin complexes, formed by antitroponin antibodies, can cause falsely elevated troponin levels, thereby complicating the diagnostic process and leading to unnecessary exercise restriction.

A 27-year-old professional cyclist presented with exercise intolerance following a viral illness. High-sensitivity troponin I was markedly elevated, while high-sensitivity troponin T remained normal. Major cardiac causes were excluded, raising suspicion for macrotroponin complexes. This was confirmed via polyethylene glycol (PEG) precipitation. The patient was cleared to return to his sports activities without the need for further monitoring.

In athletes, exercise-induced troponin release is common and may contribute to a higher prevalence of macrotroponin formation, which is an underrecognized cause of elevated troponin levels. A discrepancy between troponin I and T assay results can suggest its presence, which can be confirmed using polyethylene glycol precipitation, a simple method that helps avoid unnecessary testing, activity restrictions, and prolonged monitoring.