False Positive Cardiac Troponin Results in Patients Without Acute Myocardial Infarction

Cardiac troponin I (cTnI) and T (cTnT) are highly sensitive and specific biochemical markers for myocardial necrosis and are generally not elevated in cases other than acute myocardial infarction (AMI) and acute coronary syndrome (ACS). However, if the patient's clinical picture for AMI or ACS do not match an elevated troponin result, the laboratory should suspect a false positive troponin value caused by analytical interferences with this assay. These analytic interferences include fibrin clots, microparticles in sample, hetereophile and human anti-animal antibodies, rheumatoid factor, interference by bilirubin, hemolysis, lipemia, elevated alkaline phosphatase activity, macro immunocomplex formation, and analyzer malfunction. In general, analytical interferences resulting in false positive troponin results are associated with a specific manufacturer's troponin assay and are not encountered in all troponin assays. This review discusses steps which the laboratory should consider taking in the investigation of suspected analytical interference with the troponin assay. Awareness of the possibility of a false positive troponin result may assist the physician in the management of the patient without AMI or ACS and may spare the patient additional diagnostic procedures especially if the troponin result is not consistent with these diagnoses. A false positive troponin result is a reminder that although troponin plays an important role in the diagnosis of AMI and ACS , it should not be the only criterion for establishing these diagnoses.