**4. Cardiac biomarkers and other laboratory tests**

Laboratory investigations in perimyocarditis can reveal elevated white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and Brain natriuretic peptide (BNP) levels. Cardiac biomarkers are also elevated due to myocarditis. The incidence of elevated cardiac troponin I in patients with viral or idiopathic acute pericarditis has been reported to be 32.2%; of these patients 23.7% had a troponin I level at admission higher than those seen in myocardial infarction [28]. Elevated cardiac biomarkers in pericardial disease are not unusual and further complicate the diagnosis, raising suspicion for alternative diagnoses including myocardial infarction [29]. A study by Machdo et. al. concluded that perimyocarditis has a higher cardiac mortality than pericarditis [30]. This illustrates the importance of checking cardiac markers in all patients presenting with pericarditis. Studies also showed that elevated troponin is more common than elevated CKMB [31, 32]. The sole increase in troponin without other cardiac markers might represent a mild degree of myocardial injury.
