Cardiac biomarkers such as troponin or creatinine kinase may be elevated but normal levels do not rule out a diagnosis of myocarditis.
In one study of 88 patients with biopsy proven myocarditis only 34% had an elevated troponin I and 5.7% had an elevated CK-MB. Those patients who had duration of symptoms for less than one month were significantly more likely to have a rise in troponin which would suggest that most of the cardiac muscle cells necrose early in the disease process.
This is relevant to emergency medicine as we are most likely to see patients at the start of the inflammatory process.
Learning bite
Only about one third of patients with proven myocarditis have a troponin rise.