False positive cardiac troponin elevation due to heterophile antibodies: more common than we recognise?

Abstract

SummaryA 53-year-old woman was admitted with non-exertional chest pain and elevated cardiac troponin I (cTnI) without dynamic changes of ischaemia on the ECG. She had recently undergone coronary angiography which had shown normal coronary vessels. Repeat angiography on this admission was again unremarkable. Samples of blood were sent for analysis using different troponin assays and demonstrated chronic basal elevation of cTnI while simultaneous assay for troponin T (cTnT) remained normal. Subsequent testing revealed the presence of heterophile antibodies interfering with the troponin I assay leading to a false positive result. BACKGROUND

False Positive Troponin I Rendering Two Admissions for “Recurrent Acute Myopericarditis”

“…The authors demonstrate that a false positive troponin I test may lead to inaccurate diagnosis with important clinical implications, if clinical judgment is not used. In this case, two hospital admissions were not necessary; in other situations, as acute coronary syndrome suspicion, a false positive result lead in an unnecessary angiography [ 12 , 13 ]. As far as the authors know, this is a unique case since alkaline phosphatase interference occurred in a patient with alkaline phosphatase in the normal range.…”

A non-ischaemic cause of elevated troponin

“…As in the current case, a number of patients underwent hospital admission and, in some instances, invasive testing due to delayed realisation that the test was a false positive 16–18 21 22 24 25. Alternatively, there are several case reports in which the treating physician suspected false-positive test results in a timely manner, avoiding unnecessary admissions and hospitalisations 15 19 20 23…”

Elevation Mechanisms and Diagnostic Consideration of Cardiac Troponins under Conditions Not Associated with Myocardial Infarction. Part 2

“…The most common causes of falsely high troponin concentrations at pre-laboratory and laboratory stages are heterophilic antibodies and autoantibodies, in particular, rheumatoid factor, immune complexes, cross-reactions with skeletal muscle troponins, fibrin clots, microparticles, endogenous interference (alkaline phosphatase, hemolysis, and others), as well as malfunction of the analyzer (mechanical failures and calibration errors, use of expired reagents, etc.) [99][100][101][102][103][104][105][106].…”

“…), persistence of viral infections, therapeutic use of mouse monoclonal antibodies, or incompletely humanized (human) antibodies, etc. [99][100][101][102].…”