What are the initial laboratory tests and imaging tests for a patient presenting with chest pain?

Initial Laboratory and Imaging Tests for Chest Pain Evaluation

For patients presenting with chest pain, initial evaluation should include an ECG within 10 minutes of arrival, cardiac troponin measurement, and a chest radiograph to evaluate for cardiac, pulmonary, and other thoracic causes of symptoms. 1

Initial Assessment

History and Physical Examination

• A focused history should include pain characteristics (nature, onset, duration, location, radiation, precipitating/relieving factors) and associated symptoms to help identify potential cardiac causes 1
• Women require special attention as they may present with more accompanying symptoms (shortness of breath, fatigue) rather than classic chest pain 1
• In patients ≥75 years, ACS should be considered when accompanying symptoms like shortness of breath, syncope, acute delirium, or unexplained falls are present 1
• A focused cardiovascular examination should be performed to identify potential serious causes of chest pain and complications 1

Immediate Testing

Electrocardiogram (ECG)

• ECG should be performed within 10 minutes of arrival to evaluate for ST-segment elevation myocardial infarction (STEMI) 1
• Serial ECGs should be performed when clinical suspicion of ACS is high, symptoms persist, or clinical condition deteriorates 1
• Supplemental ECG leads V7-V9 are reasonable when posterior MI is suspected with intermediate-to-high clinical suspicion for ACS 1

Laboratory Tests

• Cardiac troponin should be measured as soon as possible after presentation in patients with suspected ACS 1
• For high-sensitivity troponin assays, recommended repeat measurement intervals are 1-3 hours after initial sample 1
• For conventional troponin assays, repeat measurements should be taken 3-6 hours after initial sample 1
• Additional laboratory tests should include hemoglobin (to detect anemia) and other markers of myocardial damage 1

Chest Radiography

• A chest radiograph is useful to evaluate for cardiac, pulmonary, and other thoracic causes of chest pain 1
• Chest X-ray can help identify conditions such as pneumonia, pneumothorax, pleural effusion, and intrathoracic tumors 1

Risk Stratification and Additional Testing

Risk Assessment

• Clinical decision pathways (CDPs) should categorize patients into low-, intermediate-, and high-risk strata to facilitate disposition and subsequent diagnostic evaluation 1
• Previous testing, when available, should be incorporated into clinical decision pathways 1

Additional Testing Based on Risk Level

• High-risk patients: Consider invasive coronary angiography 1
• Intermediate-risk patients: Consider anatomic or functional testing 1
• Low-risk patients: May defer testing or consider optional testing such as ECG or coronary artery calcium (CAC) scan 1

Special Considerations for Low-Risk Patients

• For patients with acute chest pain, normal ECG, and symptoms that began at least 3 hours before ED arrival, a single high-sensitivity troponin concentration below the limit of detection may reasonably exclude myocardial injury 1
• In patients with low suspicion for ACS, consider other diagnoses such as chest wall pain, costochondritis, gastroesophageal reflux disease, or anxiety 2

Pitfalls and Caveats

• Delayed transfer to the ED for troponin or other diagnostic testing should be avoided in patients initially evaluated in the office setting 1
• Normal ECG does not rule out ACS; careful history, clinical examination, and laboratory tests are still needed 1
• Chest pain characteristics alone are not powerful enough to rule out ACS without diagnostic testing 3
• The risk of discharging patients without correctly diagnosing ACS is significant without proper observation 1

By following this systematic approach to the evaluation of chest pain, clinicians can efficiently identify patients with life-threatening conditions while appropriately triaging those with less serious causes.