Assay interference as a cause of false positive troponin T elevation in emergency department patients

• Published in: International journal of cardiology Vol. 389; p. 131165
• Main Authors: Lyons, K.S., Herity, N., Lee, G., Talbot, C., McKeeman, G.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.10.2023
• Subjects: Assay interference; Myocardial injury; Troponin; Assay interference; Troponin; Myocardial injury
• ISSN: 0167-5273; 1874-1754
• DOI: 10.1016/j.ijcard.2023.131165

Troponin assays are used in the diagnosis of myocardial injury and may show elevated results for a variety of reasons. However it is increasingly recognised that cardiac troponin elevation may in some cases be due to assay interference. This is of significant importance as a misdiagnosis of myocardial injury may lead to unnecessary and potentially harmful investigation and treatment for patients. We sought to confirm the accuracy of cardiac high sensitivity troponin T (chsTnT) elevation in an unselected group of patients presenting to the emergency department, by using a second confirmatory cardiac high sensitivity troponin I (chsTnI) assay. We identified patients presenting to two local emergency departments over a five-day period who had chsTnT levels measured as part of routine clinical care. All samples with elevated chsTnT levels (above the 99% centile URL) were retested for chsTnI in order to confirm true myocardial injury. A total of 74 samples from 54 patients were analysed for chsTnT and chsTnI. 7 samples (9.5%) had chsTnI levels < 5 ng/L suggesting assay interference as the cause of chsTnT elevation. Assay interference leading to false positive troponin elevation may be more common than many physicians appreciate and can potentially lead to harmful investigation and treatment for patients. In cases where the diagnosis of myocardial injury is uncertain, a second alternative troponin assay should be performed to confirm true myocardial injury. •9.5% of emergency department patients with elevated troponin T levels, were found to have normal troponin I levels•False positive troponin elevation is under-recognised by physicians and may lead to unnecessary treatment for patients•The use of an alternative troponin assay may help to confirm true myocardial injury