Is D-dimer (D-dimer test) acceptable for diagnostic use in an 11-year-old female?

D-Dimer Testing in an 11-Year-Old Female

D-dimer testing is not recommended for diagnosing venous thromboembolism (VTE) in an 11-year-old female as there are no validated clinical guidelines or sufficient evidence supporting its use in the pediatric population.

Limitations of D-dimer in Pediatric Patients

D-dimer testing has been extensively studied and validated in adult populations, but evidence for its use in pediatric patients is limited:

• Current guidelines from the American Society of Hematology (ASH) and European Society of Cardiology (ESC) do not specifically address D-dimer testing in pediatric populations 1
• Age-adjusted D-dimer thresholds have been validated only for adults over 50 years of age 1, 2
• There are no validated clinical prediction rules (like Wells or Geneva scores) for determining pre-test probability of PE in pediatric populations

Evidence from Pregnancy Guidelines Provides Indirect Insight

While not directly applicable to pediatric patients, guidelines for pregnant women (another special population) highlight important limitations:

• The American Thoracic Society specifically recommends against using D-dimer to exclude suspected PE in pregnant women due to:
  • Low specificity (15%)
  • Inadequate negative likelihood ratio (1.8)
  • Documented cases of false-negative D-dimer results in the setting of confirmed PE 1

Diagnostic Approach for Suspected VTE in Pediatric Patients

In the absence of validated D-dimer protocols for children, the following approach is recommended:

1. Assess clinical presentation and risk factors for VTE
2. Proceed directly to appropriate imaging studies:
   • Compression ultrasound for suspected DVT
   • CTPA or V/Q scan for suspected PE, depending on clinical circumstances

Important Considerations

• D-dimer levels may be elevated in numerous non-thrombotic conditions including infection, inflammation, and trauma, which are common in pediatric patients 2, 3
• False negative D-dimer results can occur and may lead to missed diagnoses 1
• The normal reference ranges for D-dimer in pediatric populations have not been well established

Conclusion

Given the lack of validated protocols for D-dimer use in pediatric patients and the potential for both false positives and false negatives, clinicians should not rely on D-dimer testing for diagnosing or excluding VTE in an 11-year-old female. Instead, clinical assessment followed by appropriate imaging studies remains the recommended approach.