Long term false positive hsTnI on Alinity I probably caused by macrotroponin complex: Case report

Area of Science:

• Clinical Chemistry
• Cardiology
• Biochemistry

Background:

• Elevated cardiac troponin levels are critical biomarkers for diagnosing myocardial infarction and other cardiac conditions.
• However, analytical interferences can lead to inaccurate troponin concentrations, potentially misdirecting clinical decisions.

Observation:

• A 48-year-old female presented with persistently elevated high-sensitivity troponin I (hsTnI) levels.
• Standard laboratory investigations, including serial dilutions and antibody testing, were performed.
• Precipitation with polyethylene glycol (PEG) significantly reduced hsTnI levels, suggesting an interfering substance.

Findings:

• The persistently elevated hsTnI was attributed to the presence of macro-troponin, a complex interfering with the assay.
• Macro-troponin formation led to falsely positive hsTnI results, mimicking true cardiac injury.

Implications:

• This case underscores the importance of recognizing analytical interferences, such as macro-troponin, in hsTnI testing.
• Accurate interpretation of troponin levels requires awareness of potential interfering factors to avoid misdiagnosis of cardiac disease.
• Implementing specific diagnostic procedures, like PEG precipitation, can help identify and resolve such interferences.