Since January 2014 to December 2016, there were 35 patients with venous thromboembolism treated in Nhan dan Gia Dinh Hospital, HCMC They were diagnosed with deep vein thrombosis by using Doppler ultrasound the lower limbs' veins from the ankles to the inguinal folds in both legs or diagnosed with pulmonary embolism by using contrast-enhanced chest CT.