Cardiac Biomarkers—Are We Testing Wisely?

Cardiac biomarker testing, along with a thorough patient history, physical exam, and an electrocardiogram, is required for the diagnosis of patients with suspected acute coronary syndrome (ACS). For nearly 3 decades, 2 cardiac biomarkers, troponin (I or T) and creatine kinase-MB fraction (CK-MB), have been ordered together to evaluate ACS patients out of concern that utilizing a single biomarker might be less diagnostically accurate than using 2 biomarkers. However, subsequent studies have shown that troponin is far more sensitive and specific for myocardial injury than CK-MB. 1,2 Troponin testing offers important prognostic information irrespective of whether the CK-MB is normal or abnormal. In 2015, the American Society of Clinical Pathology released a Choosing Wisely recommendation against ordering CK-MB (or myoglobin) for the diagnosis of acute myocardial infarction (AMI). This reflects an emerging consensus that CK-MB testing represents low-value care while troponin testing alone is the appropriate diagnostic strategy for ACS patients.