Persistently elevated cTn levels without supporting clinical or imaging evidence represent a common diagnostic challenge during myocarditis follow-up. A retrospective cohort study published in the International Journal of Cardiology evaluated the contribution of assay interferents to misleading cTn results in patients with prior myocarditis and discordant findings.

Between 2005 and 2024, 1,143 patients with myocarditis were followed at a single center. Of these, 29 patients underwent targeted testing for cTn assay interference because of long-standing low-level troponin elevation, minimal or atypical symptoms, unremarkable ECG findings, and normal coronary arteries. cTnI and cTnT were measured using fully automated chemiluminescent two-site immunoassays.

Assay interferents were identified in 31% of tested patients. In interferent-positive cases, cTn levels at the time of testing were significantly lower than at initial diagnosis (150 vs 776 ng/L; P = 0.018). In 8 of 9 cases, identification of interference helped exclude suspected myocarditis relapse.

Among patients without detectable interferents, interference testing alone influenced treatment decisions or indications for invasive procedures in 25% of cases. Overall, consideration of cTn assay interference affected clinical management in nearly half of evaluated patients, supporting a selective approach to interferent testing when biochemical and clinical findings are discordant.