False-positive cardiac troponin I in a routine clinical population

Fleming, S; O'Byrne, L; Finn, Joseph D.; Grimes, H.; Daly, Kieran

doi:10.1016/s0002-9149(02)02309-3

Cited by 68 publications

(37 citation statements)

References 18 publications

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“…Whether a cTn rise is true positive or FP (technical FP, biochemical FP, analytic FP, »true« FP) may depend on the type of cTn measured. Sometimes, for example, cTnT is FP, but cTnI is not (24). Renal failure is one of the most important conditions with diverse cTnT and cTnI results.…”

Section: What Are the Causes Of Analytic No Actual Myocardial Damagementioning

confidence: 99%

False Positive Troponin – A True Problem

Koraćević¹,

Ćosić²,

Stojanović³

2013

Journal of Medical Biochemistry

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Summary Cardiac troponins have a crucial role in diagnosing acute myocardial infarction, but have been considered by some authors to have a high false positive rate. Such opinions may decrease the confidence in troponin with important clinical consequences. The aim of the paper is to analyze three different meanings of the phrase »false positive troponin«: A) analytic (technical) false positive, with no real myocardial damage; B) false positive considering AMI: cardiac injury is present, but there is no AMI; C) false positive considering CAD: there is myocardial damage, but no CAD. The most frequent and the most important source of misunderstanding is the confusion between aspects A) and B). Namely, there has been a relatively small percentage of false positive troponin elevations due to analytic reasons. On the contrary, there has been a re - latively large percentage of »false positive« results in patients with myocardial necrosis due to causes other than AMI; for them - instead of »FP troponin elevation« - another phrase ought to be used, e.g., »non-AMI troponin elevation « until the etiopathogenesis in an individual patient is recognized. The phrase »false positive troponin« should be restricted to the artificial increase in troponin due to preanalytic and analytic reasons. By doing so, we may decrease the degree of confusion about troponin and increase the confidence in this highly specific marker of myocardial injury. The possibility of an analytic false positive result should always be kept in mind when one interprets elevated troponin.

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Section: What Are the Causes Of Analytic No Actual Myocardial Damagementioning

confidence: 99%

False Positive Troponin – A True Problem

Koraćević¹,

Ćosić²,

Stojanović³

2013

Journal of Medical Biochemistry

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“…7 The European Society of Cardiology (ESC)/ACC consensus document on MI, as well as multiple trials in UA/NSTEMI, supports a very low cut-point for troponin elevation as a biomarker of adverse outcome in patients presenting with a clear history of ischemic symptoms. 1,[5][6][7][8] It should be noted however, that in patients without a clear history, troponin elevations in the absence of ischemia have been reported 9,10 and can be caused by congestive heart failure, 11 pulmonary embolism, 12 or technical problems with the assay. 10 Thus, in patients with an unclear history, small troponin elevations may not be diagnostic of acute coronary syndromes (ACS).…”

Section: Cardiac Biomarkersmentioning

confidence: 99%

“…1,[5][6][7][8] It should be noted however, that in patients without a clear history, troponin elevations in the absence of ischemia have been reported 9,10 and can be caused by congestive heart failure, 11 pulmonary embolism, 12 or technical problems with the assay. 10 Thus, in patients with an unclear history, small troponin elevations may not be diagnostic of acute coronary syndromes (ACS). In contrast, among patients with a clinical history suggestive of myocardial ischemia, troponin elevations have very strong prognostic implications of adverse outcomes.…”

Section: Cardiac Biomarkersmentioning

confidence: 99%

Unstable Angina and Non–ST-Elevation Myocardial Infarction

Cannon

Turpie

2003

Circulation

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“…Recent studies from my own laboratory have demonstrated that false positive TnI results occur with both serum and lithium heparin sample types with BD tubes (2) and Greiner tubes, at a rate of 14/1000 samples on both the Access 2 and DxI800 analysers (3). These and other publications since then have attributed the errors to residual fibrin (1,4,5). The discrepant results are rarely reproducible.…”

mentioning

confidence: 99%

“…False positive troponin I (TnI) results with the Beckman AccuTnI method have been reported since 2002 (1). Recent studies from my own laboratory have demonstrated that false positive TnI results occur with both serum and lithium heparin sample types with BD tubes (2) and Greiner tubes, at a rate of 14/1000 samples on both the Access 2 and DxI800 analysers (3).…”

mentioning

confidence: 99%

Evidence on the cause of false positive troponin I results with the Beckman AccuTnI method

Dimeski¹

2011

Clinical Chemistry and Laboratory Medicine

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Keywords: false positive; insoluble fibrin; troponin I. (2) and Greiner tubes, at a rate of 14/1000 samples on both the Access 2 and DxI800 analysers (3). These and other publications since then have attributed the errors to residual fibrin (1, 4, 5). The discrepant results are rarely reproducible. The strategy employed to minimise erroneous results from being reported has been to utilise aliquots of serum or plasma and re-centrifuge the aliquot at centrifugation settings routinely used or at high speeds (6). In our laboratory, the strategy is to utilise the analyser's reflex function and analyse samples in duplicate when the result is )0.04 and -5.00 mg/L. Results outside these limits have been very rarely observed to produce false positive results and thus are not run in duplicate. If the duplicate results exceed a difference of 20% or more, which is considered clinically significant and needs investigation, an aliquot is re-centrifuged and the supernatant re-analysed. The third (and fourth replicate if produced) are reviewed in conjunction with other pathology results and clinical information before a result is reported. It is by no means a fool proof process, and on very rare occasion false positive results continue to be reported at a rate of one result in approximately 4000 samples. The downside with the process, as pointed out by Pfafflin, is that there can be delays in reporting of results and potential delays in diagnosis of myocardial infection (6). The delay in reporting of TnI results with this procedure is justified by minimisation of result inaccuracies, reducing the number of patients falsely diagnosed or being exposed to unnecessary stress with additional testing, treatment and admission. The cost of the reagent and other consumables are easily accounted for by preventing the inappropriate admission of a few patients each year, and preventing potential legal and professional implications.The exact cause of the problem has not been identified nor has anyone shown residual fibrin or any other analyte being directly linked to the problem. Lithium heparin plasma samples stored at 48C containing ''insoluble fibrin'' mesh were used to demonstrate the impact of sample quality resulting in non-specific binding and the lack of method robustness. Such insoluble fibrin is observed after 24 h of storage at 2-88C in about 5% of samples in our laboratory. Insoluble fibrin is formed from fibrinogen, and fibrinogen is present in lithium heparin plasma. Fibrin formation and fibrin structure is stated to be influenced by a number of variables including fibrinogen and thrombin concentrations, pH, ionic strength, chloride ion concentration, presence of calcium ions, and polyphosphate, a potent anticoagulant (7). Disease state and medication can both diminish the efficacy of heparin activity and lead to increased fibrin formation, and this is enhanced when plasma is stored at low temperature (8).In our laboratory, blood tubes (lithium heparin plasma and serum) are centrifuged for 10 min at 208C and 3000 g (approx. 4...

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False-positive cardiac troponin I in a routine clinical population

Cited by 68 publications

References 18 publications

False Positive Troponin – A True Problem

False Positive Troponin – A True Problem

Unstable Angina and Non–ST-Elevation Myocardial Infarction

Evidence on the cause of false positive troponin I results with the Beckman AccuTnI method

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