What are the diagnostic criteria for Pulmonary Embolism (PE)?

From the Guidelines

Pulmonary embolism (PE) diagnosis should be approached using a combination of clinical assessment, laboratory tests, and imaging studies, with the initial evaluation including a clinical probability assessment using validated tools like the Wells score or Geneva score, as recommended by the American College of Physicians 1. The diagnostic criteria for PE involve a stepwise approach, starting with clinical probability assessment, followed by D-dimer testing for patients with low or intermediate clinical probability, and imaging studies such as CT pulmonary angiography (CTPA) for those with high clinical probability or positive D-dimer results. Some key points to consider in the diagnostic approach include:

• Using validated clinical prediction rules to estimate pretest probability in patients with suspected PE 1.
• Applying the Pulmonary Embolism Rule-Out Criteria (PERC) to patients with low pretest probability to determine if D-dimer testing is necessary 1.
• Using age-adjusted D-dimer thresholds (age × 10 ng/mL) in patients older than 50 years to determine if imaging is warranted 1.
• Obtaining imaging with CTPA in patients with high pretest probability of PE, reserving ventilation-perfusion scans for patients with contraindications to CTPA or if CTPA is not available 1. The most recent evidence from 2022 supports the use of CTPA as the gold standard for PE diagnosis, with a focus on integrating clinical presentation, laboratory tests, and imaging studies to provide high-value care 1. Overall, the diagnostic approach to PE should prioritize a combination of clinical assessment, laboratory tests, and imaging studies, with a focus on using the most recent and highest-quality evidence to guide decision-making.

From the Research

Diagnostic Criteria for Pulmonary Embolism

The diagnosis of pulmonary embolism (PE) relies on a combination of clinical assessment and objective diagnostic testing. The following are the key diagnostic criteria:

• Clinical decision rules, such as the Wells score, can determine the pre-test probability of PE 2
• If PE is "unlikely", a D-dimer test can be used to rule out PE 3, 4
• If the D-dimer result is normal, PE can be excluded 3, 4
• If D-dimer levels are increased, chest imaging, such as computed tomography pulmonary angiogram (CTPA) or ventilation-perfusion (VQ) scan, is recommended 3, 4, 2
• CTPA is the preferred imaging modality for diagnosing PE, but VQ scans can be used as an alternative in patients with contraindications to CTPA 3, 4, 2

Clinical Decision Tools

Clinical decision tools, such as the Wells criteria and revised Geneva score, can assist physicians in determining when to perform CTA to evaluate suspected PE 5

• These tools have varied accuracy in identifying PE, and may fail to identify a significant number of positive PE cases 5
• Alternative D-dimer cutoffs, such as >300 μg/L, may provide better accuracy in identifying PE cases 5

Diagnostic Strategy

The diagnostic strategy for PE should be based on clinical evaluation of the probability of PE 6

• The accuracy of diagnostic tests for PE is high when the results are concordant with the clinical assessment 6
• Additional testing is necessary when the test results are inconsistent with clinical probability 6