Multiple admissions to the coronary care unit due to falsely elevated cardiac troponin
Mohamed Ayan1, Zaid Gheith1, Aneesha Ananthula1
1Department of Cardiovascular Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
Insights
False-positive cardiac troponin results can occur due to heterophile antibodies. This case highlights the importance of considering assay interference when clinical data conflicts with troponin levels.
Area of Science:
- Cardiology
- Clinical Chemistry
- Immunology
Background:
- Cardiac troponin measurement is crucial for diagnosing acute myocardial infarction.
- Elevated troponin levels can be observed in various non-ischemic conditions, necessitating careful clinical correlation.
- Assay interference, particularly from heterophile antibodies, can lead to inaccurate troponin measurements.
Observation:
- A 94-year-old male with coronary artery disease presented with altered mental status and persistently high troponin levels.
- Despite multiple admissions for non-cardiac complaints, clinical suspicion for myocardial infarction was low.
- Discordance between clinical presentation and laboratory findings prompted further investigation.
Findings:
- Immunological interference from heterophile antibodies in the AccuTnI+3 assay was suspected.
- Testing the same serum sample on a different assay (Roche Elecsys Troponin I) yielded undetectable troponin levels.
- This confirmed a false-positive troponin result due to assay interference.
Implications:
- Highlights the potential for heterophile antibodies to cause false-positive cardiac troponin results.
- Emphasizes the critical need for considering assay interference in discordant clinical and laboratory findings.
- Suggests the utility of using alternative troponin assays to resolve discrepancies and ensure accurate diagnosis.
Abstract:
The measurement of cardiac troponin, released from injured cardiomyocytes, is of paramount importance in the diagnosis of acute myocardial infarction. Elevated troponin can be encountered, however, in patients with cardiomyopathy, significant cardiac arrhythmias, vasculitis, right-sided heart strain, critical systemic illnesses, stroke, drug toxicity (such as Adriamycin), poisons (such as snake venoms), renal failure, seizure, and rhabdomyolysis. If the clinical picture is not consistent with any of these causes, a false-positive result should be considered. We herein describe a 94-year-old man with a prior history of coronary artery disease who presented with altered mental status and was found to have a persistently high troponin level resulting in three admissions to the coronary care unit for various noncardiac complaints. Because of discordance between clinical and laboratory data, immunological interference due to heterophile antibodies in the locally used assay (AccuTnI+3, Beckman Coulter) was suspected. The same serum sample tested on a different assay (Elecsys Troponin I Assay, Roche) resulted in an undetectable cardiac troponin I level, thus confirming the diagnosis.
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