D-Dimer Testing in Pulmonary Embolism Diagnosis

Diagnostic Value of D-Dimer

The European Society of Cardiology recommends D-Dimer tests as a diagnostic tool for pulmonary embolism, with a high negative predictive value, meaning a normal D-Dimer value makes acute pulmonary embolism or deep vein thrombosis unlikely 1
The positive predictive value of elevated D-Dimer values is low, making D-Dimer tests unsuitable for confirming pulmonary embolism 1, 2
The specificity of D-Dimer decreases with increasing age, down to about 10% in patients over 80 years old 3, 4

A D-Dimer value > 5 mg/ml is associated with a positive predictive value of 50% for thrombotic complications, according to the COVICLOT study 5
In hospitalized patients, a D-Dimer value > 5611 ng/ml is independently associated with the diagnosis of venous thromboembolism during hospital stay (OR 6.3, 95% CI 2.4-16.2) 5

The European Respiratory Society suggests using age-adjusted D-Dimer thresholds to improve the performance of D-Dimer tests in older patients 2, 3
A multicenter, prospective management study evaluated an age-adjusted D-Dimer threshold (age × 10 μg/L for patients over 50 years) in a cohort of 3346 patients, increasing the number of patients in whom pulmonary embolism could be excluded from 43 (6.4%) to 200 (29.7%) 2, 3

The European Society of Cardiology recommends using validated clinical prediction rules, such as the Wells criteria or revised Geneva score, to assess pre-test probability in patients with suspected pulmonary embolism 6
In patients with elevated D-Dimer, multidetector CT pulmonary angiography (CTPA) is recommended as the next step, which is diagnostic for pulmonary embolism if it shows a clot at least at the segmental level of the pulmonary arterial tree 1, 2