D-dimer

Differential Diagnosis

  • Factors that can cause false-negative D-dimer
    • Symptoms of PE > 3 days
    • Small PE
    • Use of qualitative latex fixation test
    • Use of anticoagulants
  • Factors that can cause false-positive D-dimer
    • Cancer and malignancy
    • Recent surgery
    • Infection (eg, PNA, sepsis)
    • Pregnancy
    • Age > 70 years
    • DIC
    • Trauma
    • Arterial thrombosis
    • ACS/AMI
    • Vaso-occlusive sickle cell crisis
    • Acute CVA
    • Vasculitis
    • Superficial phlebitis

Diagnosis

  • Traditional cutoff value = 500
  • Age-adjusted (for over 50 years old) = age x 10
    • Maintains high sensitivity while increasing specificity[1]

See Also

References

  1. Sharp AL, et al. An Age-Adjusted D-dimer Threshold for Emergency Department Patients with Suspected Pulmonary Embolus: Accuracy and Clinical Implications. Feb 2016. Annals of EM. 67(2);249-257.