Best Next Step: Send D-dimer
In this young woman with pleuritic chest pain, normal vital signs, and low-to-intermediate pretest probability of PE, the best next step is to obtain a high-sensitivity D-dimer measurement. 1
Risk Stratification Framework
This patient requires systematic pretest probability assessment before any testing:
- She has a PE risk factor (estrogen-based oral contraceptives increase thrombotic risk) 1
- Clinical presentation includes pleuritic chest pain (pain with deep breathing), which is consistent with but not specific for PE 1
- Normal vital signs and physical examination suggest she is not in the high-risk category 1
Why D-dimer is the Correct Initial Test
The American College of Physicians guidelines provide clear algorithmic guidance for this exact scenario 1:
For patients with low or intermediate pretest probability who do NOT meet all Pulmonary Embolism Rule-Out Criteria (PERC), obtain a high-sensitivity D-dimer as the initial diagnostic test. 1
- This patient likely does not meet all 8 PERC criteria because she is taking estrogen-based contraceptives (a hormone use criterion) 1
- D-dimer should be the initial test—NOT imaging—in patients with low or intermediate pretest probability 1
- A negative D-dimer (below age-adjusted cutoff) effectively rules out PE without need for CT imaging 1
- An elevated D-dimer would then warrant CT pulmonary angiography 1
Why Other Options Are Incorrect
Applying PERC and discharging: While PERC can identify very low-risk patients who need no testing, this patient has a PE risk factor (oral contraceptives) and likely fails at least one PERC criterion, making this approach inappropriate 1
Ordering CT chest angiogram directly: This violates evidence-based guidelines that explicitly state "Clinicians should not use imaging studies as the initial test in patients who have a low or intermediate pretest probability of PE" 1. Direct-to-CT imaging:
- Exposes young women to unnecessary radiation with cancer risk to radiosensitive breast tissue 1
- Results in contrast nephropathy risk 1
- Leads to overdiagnosis of clinically insignificant PEs 1
- Is not cost-effective when D-dimer can safely exclude PE in many patients 1
Ordering transthoracic echocardiogram: Echocardiography is reserved for hemodynamically unstable patients with suspected massive PE to assess right ventricular strain 1. This stable patient with normal vital signs does not meet criteria for this approach.
Critical Clinical Pitfall
The most common error is ordering CT angiography without first obtaining D-dimer in low-to-intermediate risk patients. Studies show approximately one-third of patients who receive CT for PE either had no D-dimer performed or had a negative D-dimer result, representing inappropriate testing 1. This practice pattern contributes to the documented increase in PE diagnosis without corresponding mortality benefit 1.
Age Consideration for D-dimer Interpretation
Since this is a young woman (likely under 50 years old based on description), use the standard cutoff of <500 ng/mL rather than age-adjusted thresholds, which apply only to patients over 50 years 1.