Management of Low Suspicion PE with PERC-Negative and D-dimer 1.59
No further imaging is needed; pulmonary embolism is safely excluded in this patient. 1
Critical Interpretation Issue
There appears to be a contradiction in your clinical scenario that needs clarification:
- PERC-negative status means the patient should NOT have had D-dimer testing performed 1
- When all 8 PERC criteria are met (PERC-negative), the risk of PE is lower than the risks of testing, and D-dimer should not be ordered 1
- The diagnostic pathway shows: Low suspicion → Apply PERC → If PERC-negative → Stop, no further testing 1
Assuming PERC-Positive (D-dimer Was Appropriately Ordered)
If the patient was actually PERC-positive (failed one or more PERC criteria), then D-dimer testing was appropriate. With a D-dimer of 1.59 (assuming units of µg/mL or 1590 ng/mL):
Standard D-dimer Cutoff Approach
- Proceed to imaging with CT pulmonary angiography (CTPA) 1
- Any D-dimer >500 ng/mL (or >0.5 µg/mL) in a low pretest probability patient requires imaging 1
- An elevated D-dimer level should lead to imaging studies 1
Age-Adjusted D-dimer Consideration
- For patients over 50 years old, use age-adjusted cutoff (age × 10 ng/mL) 2
- Example: A 60-year-old would have a cutoff of 600 ng/mL (0.6 µg/mL) 2
- If your patient is >159 years old (clearly impossible), only then would 1590 ng/mL be considered negative 2
- Since 1.59 µg/mL exceeds any reasonable age-adjusted cutoff, imaging is required 2
Alternative Imaging if CTPA Contraindicated
If the patient cannot receive IV contrast: 3, 4
- First-line alternative: Ventilation-perfusion (V/Q) scan 4
- Second option: Lower extremity venous ultrasound 3
- A positive DVT finding would confirm venous thromboembolic disease and may preclude need for additional imaging 3
Common Pitfalls to Avoid
- Never apply PERC to patients over 50 years old as age <50 is one of the eight required criteria 2
- Never order D-dimer in truly PERC-negative patients as this represents unnecessary testing 1
- Never use standard 500 ng/mL cutoff for older patients when age-adjusted values are more appropriate 2
- Never skip imaging when D-dimer is elevated in low or intermediate probability patients 1
Clinical Bottom Line
Order CTPA immediately 1. The D-dimer of 1.59 (1590 ng/mL) is elevated regardless of whether you use standard (>500 ng/mL) or any reasonable age-adjusted cutoff, mandating pulmonary vascular imaging to exclude PE 1, 2.