Introduction Pulmonary Embolism (PE), the most serious complication of Deep Vein Thrombosis (DVT), is a relatively common and potentially fatal disease. Its diagnosis usually requires multiple approaches based on diagnostic imaging such as ventilation/perfusion lung scanning (V/Q) or Computed Tomography (CT). However, the performance of such imaging cannot immediately be performed in case of night or week-end referral; in this situation, attending physicians have to decide whether to treat incompletely assessed patients or to hospitalise them until confirmatory tests can be carried out. In lack of guidelines, empirical protective anticoagulation with Low Molecular Weight Heparins (LMWH), drugs showing a more favourable pharmacodynamic profile in comparison to UnFractionated Heparins (UFH), is usually given to patients. However, no clear-cut information is available about the need of such anticoagulation, its dosage and duration, or the time over which deferral of diagnostic procedures can be considered as safe. It seems more appropriate and safer, though, a management based on a preliminary evaluation of the actual risk of thrombosis.