Because a significant number of the deaths caused by acute (massive) pulmonary thromboembolism occur within the hours after the onset of symptoms, its early diagnosis is very important. The gold standard diagnostic tests for venous thromboembolism (VTE), contrast venography and pulmonary angiography, respectively, are invasive, expensive, not readily available, and labor intensive. A diagnostic tool for VTE is needed that is noninvasive and highly accurate, allowing immediate treatment decisions to be made in most cases. D-dimer, a one of haemostatic molecular markers, is specific cross linked fibrin derivatives. This is the most promising blood test for VTE screening. Although elevated concentrations of D-dimers are sensitive for the presence of VTE, they are not specific. They therefore cannot be used to make a positive diagnosis of VTE.