Non-Reproducible Troponin Results Are More Common Than Biotin Interference and Clinically Dangerous
This systematic review highlights an underappreciated analytical pitfall: non-reproducible cardiac troponin results ("fliers" or "outliers") that yield significantly different values when re-measured on the same sample. With a reported prevalence of 0.28-0.57%, these outliers are more frequent than biotin interference and can trigger inappropriate clinical decisions. The authors present four illustrative cases and call for routine duplicate testing protocols when results are clinically discordant.
The original study
The underestimated issue of non-reproducible cardiac troponin I and T results: case series and systematic review of the literature.
- Authors
- Favresse J, Bayart JL, Gruson D, Bernardini S, Clerico A, Perrone M
- Journal
- Clinical chemistry and laboratory medicine
- Type
- Journal Article, Systematic Review
- PMID
- 33554552
Original abstract
Cardiac troponins (cTn) are the preferred biomarkers for the evaluation of myocardial injury and play a key role in the diagnosis of acute myocardial infarction (MI). Pre-analytical or analytical issues and interferences affecting troponin T and I assays are therefore of major concern given the risk of misdiagnosis. False positive troponin results have been related to various interferences including anti-troponin antibodies, heterophilic antibodies, or elevated alkaline phosphatase level. On the other hand, false negative results have been reported in the case of a large biotin intake. These interferences are characterized with erroneous but reproducible troponin results. Of interest, non-reproducible results have also been reported in the literature. In other words, if the sample is reanalyzed a second time, a significant difference in troponin results will be observed. These interferences have been named "fliers" or "outliers". Compared to the biotin interference that received major attention in the literature, troponin outliers are also able to induce harmful clinical consequences for the patient. Moreover, the prevalence of outliers in recent studies was found to be higher (0.28-0.57%) compared to the biotin interference. The aim of this systematic review is to warn clinicians about these non-reproducible results that may alter their clinical judgment. Four case reports that occurred in the Clinique of Saint-Luc Bouge are presented to attest this point. Moreover, we aimed at identifying the nature of these non-reproducible troponin results, determining their occurrence, and describing the best way for their identification.