D-Dimer concentrations increase following the thrombotic event and decrease thereafter. Timing of D-Dimer evaluation in relation to the onset of the disease might have a diagnostic impact. We have presently performed a retrospective analysis of diagnostic procedures performed in individuals who presented to the Emergency department and evaluated for acute venous thromboembolism (VTE) following a single quantitative D-Dimer testing. Individuals who had a negative objective test served as controls to those who had a positive one (Doppler ultrasonography, high probability lung scan or a CT angiography). Seven hundred thirty-four individuals presented to the Emergency department, performed a single D-Dimer test as well as an objective test during their evaluation for an eventual event of acute VTE. One hundred ninety-seven patients had a positive objective test for either deep vein thrombosis (DVT) or pulmonary embolus. They were divided into seven tiles of times from symptoms onset. Highly significant differences between patients and controls regarding D-Dimer concentrations were noted mainly during the early days from symptom onset and turned less significant thereafter. Taking into consideration the time from symptoms onset in patients with acute VTE might have an effect on the diagnostic yield of quantitative D-Dimer in the Emergency department. We suggest not to exclude the eventual presence of acute VTE if quantitative D-Dimer is obtained later than 1 week following the onset of symptoms.