The false positive troponin results: case studies of analytical interference

Cardiac troponin I and T are particularly sensitive and specific markers for cardiomyocyte damage. Myocardial injury can occur due to a discrepancy between oxygen supply and demand (eg coronary artery occlusion and arrhythmias), other cardiac causes (eg pericarditis, myocarditis, cardiac surgery, cardioversion etc) or systemic conditions (eg sepsis, stroke and chronic renal disease). The latest European Society of Cardiology guidelines help to guide clinicians through these different causes. Occasionally troponin concentrations may not fit the clinical presentation and, therefore, other aetiologies should be considered. An under-appreciated basis of a high troponin concentration is a false positive result, which can be attributable to analytical interference from components in the patient's blood. Uncovering this interference can be pivotal to avoid unnecessary and potentially harmful investigations or treatment for patients. We present two cases of false positive troponin results caused by analytical interference. The normal reference range for the assay (Access; Beckman Coulter, High Wycombe, UK) used at our organisation is 0-18 ng/L.