From the Guidelines
You can stop trending troponins once a clear peak has been identified and levels have begun to decrease, or after serial negative measurements have effectively ruled out myocardial injury, typically requiring at least 2-3 measurements over 6-12 hours. For patients with suspected acute coronary syndrome, obtain an initial troponin on presentation, followed by a second measurement 3-6 hours later, and potentially a third at 6-12 hours if clinical suspicion remains high despite normal initial values 1. The timing of troponin measurements is based on the protein's release kinetics following cardiac injury, with levels typically rising within 3-4 hours of injury, peaking at 24-48 hours, and potentially remaining elevated for 7-14 days.
Key Considerations
- In patients with confirmed myocardial infarction, continue measurements until the peak is clearly established, which may require 3-4 readings.
- Patients with renal dysfunction may have persistently elevated baseline troponin levels, requiring clinical correlation rather than absolute values.
- The 99th percentile of the upper reference level is the appropriate cutpoint for considering myocardial necrosis, and evidence for a serial increase or decrease ≥20% is required if the initial value is elevated 1.
Clinical Application
- Troponin levels should be trended until they peak and begin to decline.
- Clinical laboratory reports should indicate whether significant changes in cardiac troponin values for the particular assay have occurred.
- Point-of-care troponin values may provide initial diagnostic information, although their sensitivity is substantially below that of central laboratory methods 1.
From the Research
Troponin Trending in Acute Coronary Syndromes
- The decision to stop trending troponins is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
- However, it is mentioned that high-sensitivity troponin measurements are the preferred test to evaluate for non-ST-segment elevation myocardial infarction (NSTEMI) 2.
- The studies focus on the diagnosis, treatment, and management of acute coronary syndromes, including the use of troponin levels to assess cardiovascular risk and guide treatment decisions 2, 3, 4, 5, 6.
- Peak troponin levels have been associated with cardiovascular mortality and adverse cardiovascular events, and predictors of peak troponin levels include ST-elevation myocardial infarction, SYNTAX score, and prior aspirin use 5.
- There is no specific guidance on when to stop trending troponins, as this decision likely depends on individual patient factors and clinical judgment.