What are the clinical indications for not drawing a second troponin level in a patient with chest pain?

From the Guidelines

A second troponin level does not need to be drawn in patients with chest pain if a single high-sensitivity troponin concentration is below the limit of detection on initial measurement and symptoms began at least 3 hours before ED arrival.

Clinical Indications

• A normal ECG and symptoms suggestive of ACS that began at least 3 hours before ED arrival, with a single hs-cTn concentration below the limit of detection on initial measurement (time zero) 1
• Patients who are classified as low-risk using a clinical decision pathway, such as the HEART Pathway, EDACS, ADAPT, or mADAPT, with initial and serial cTn/hs-cTn below the assay 99th percentile 1

Key Considerations

• The timing of chest pain onset relative to ED arrival is critical, with a minimum of 3 hours before ED arrival required for a single hs-cTn measurement to be reliable 1
• The type of troponin assay used, either high-sensitivity or conventional, must be taken into account when interpreting results 1
• Clinical decision-making based on single measurement of conventional cTn has not been validated, and serial measurements are recommended 1

From the Research

Clinical Indications for Not Drawing a Second Troponin Level

The decision to not draw a second troponin level in a patient with chest pain is based on several clinical indications. These include:

• Patients with a low clinical suspicion of acute coronary syndrome (ACS) 2
• Patients with a non-cardiac cause of chest pain, such as myocarditis or pericarditis 3
• Patients with mildly increased cardiac troponin concentrations, but no other signs or symptoms of ACS 4
• Patients without chest pain or electrocardiographic ischemic changes, as elevated troponin values in these patients may not have clinical utility 5

Specific Patient Populations

Certain patient populations may not require a second troponin level, including:

• Pediatric patients with chest pain, as the utility of troponin measurements in this population is not well defined 3
• Patients without typical symptoms of ACS, such as chest pain, as troponin testing may not be necessary in these cases 6
• Patients with anginal equivalent symptoms, such as shortness of breath or general weakness, as troponin testing may not be necessary unless the patient has a high-risk profile 6

Laboratory Results

Laboratory results can also guide the decision to not draw a second troponin level, including:

• Patients with troponin levels below a certain threshold, such as 0.1 ng/ml 3
• Patients with high-sensitivity cardiac troponin T (hs-cTnT) concentrations below 14 ng/L 4
• Patients with cardiac troponin I (cTnI) levels below 0.2 microg/L 6