Research indicates that no tests of a single cardiac marker are 100% specific and sensitive for diagnosis of AMI in all patients. Each biomarker has advantages and disadvantages (see Table). Over-reliance on a single diagnostic test is risky. Specific tests should be ordered on the basis of the individual patient's assessment and medical history. Nurses are an important link in the collection of patients' medical history and in assessment as well as in the interpretation of patients' laboratory results. A knowledge of diagnostic tests commonly used in the care of patients with ischemic heart disease is imperative if patients are to receive appropriate, timely, cost-effective care.