A 32-year-old woman presents to the outpatient clinic with a 1-day history of right-sided pleuritic chest pain and mild dyspnea. Her vital signs show a temperature of 37.1°C (98.8°F), pulse of 92/min, respiratory rate of 16/min, and blood pressure of 118/76 mm Hg. Oxygen saturation is 99% on room air. She has no history of venous thromboembolism, recent surgery, or immobilization. Her physical examination is unremarkable. Arrange the following diagnostic steps in the most appropriate sequential order for the evaluation of this patient.
- 1Assess pretest clinical probability using a validated scoring system (e.g., Wells criteria).
- 2Measure high-sensitivity plasma D-dimer levels.
- 3Perform computed tomography pulmonary angiography (CTPA).
Answer
The correct sequence is to first assess the pretest clinical probability, followed by measuring D-dimer levels, and finally performing a computed tomography pulmonary angiography if indicated.
The correct sequence reflects the standard evidence-based algorithm for evaluating suspected pulmonary embolism in a hemodynamically stable patient. The first priority is always to establish the pretest probability using a scoring system like the Wells criteria. Because this patient is young, has no significant risk factors, and has stable vital signs, her pretest probability is low. For low-risk patients, a high-sensitivity D-dimer test is the most appropriate next step because a negative result non-invasively rules out a pulmonary embolism. Computed tomography pulmonary angiography (CTPA) should only be performed subsequently if the D-dimer test is positive.
Step-by-Step Solution
Key Concept
Diagnostic algorithm for hemodynamically stable suspected pulmonary embolism based on clinical pretest probability