[Comment] D-dimer thresholds in pulmonary embolism: avoiding one-size-fits-all

The standard testing for pulmonary embolism includes a two-step or three-step algorithm (ie, the assessment of pretest probability with validated clinical decision rules [CDRs], ordering a D-dimer test, and/or a CT pulmonary angiography [CTPA]). This approach offers an excellent negative predictive value.1 However, its specificity is poor and there is an increasing concern of overtesting, mainly regarding an excessive use of CTPA. A multicentre study showed that approximately 2% of patients at emergency department visits underwent CTPA to rule out pulmonary embolism, with a pooled yield rate of 3%.