Change in Troponin Assay Reference Range
Thursday, April 25, 2019
To Our Clients of Laboratory Alliance
Effective May 15, 2019
Based on the Expert Consensus Document, “The Fourth Universal Definition of Myocardial Infarction (2018)”, published by an international task force that includes the American College of Cardiology and the American Heart Association, the reference range for Troponin I will be updated to <0.05 ng/mL, which represents the 99th percentile of patients without cardiac injury.
- Myocardial injury is present when there is evidence of elevated troponin values with at least one value above the 99th percentile upper reference limit. Myocardial injury should be considered acute if there is a rise and/or fall of troponin values.
- Myocardial infarction should be considered when there is acute myocardial injury with clinical evidence of acute myocardial ischemia and with detection of a rise and/or fall of troponin values with at least one value above the 99th percentile upper reference limit and at least one of the following:
- Symptoms of myocardial ischemia;
- New ischemic ECG changes;
- Development of pathological Q waves;
- Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality in a pattern consistent with an ischemic etiology;
- Identification of a coronary thrombus by angiography or autopsy (not for Type 2 or 3 MIs).
- The Troponin I reference range will updated from 0.00-0.10 ng/mLto <0.05 ng/mL effective May 15, 2019.
- The lowest reportable value for Troponin I will be changed from 0.06 ng/mL to 0.05 ng/mL. Values below 0.05 ng/mL will be reported as <0.05 ng/mL.
- The laboratory report will be updated to include the following interpretive comments:
Less than 0.05: Myocardial injury unlikely
Greater than or equal to 0.05: Highly suggestive of myocardial injury.
Correlation with rise and/or fall of serial troponins, clinical symptoms, and ECG changes is necessary.