Background and Objective: D-dimer has emerged as a simple blood test can be used in diagnostic algorithms for the exclusion of venous thromboembolism (VTE). However D-dimer assays have low specificity and may increase radiographic testing for VTE. The aim of this study was to find a new cut-off value for VTE in Korean populations and to find factors associated with false positive D-dimer result. Methods: From January 2009 to December 2009, a total of 2,048 patients (988 men, 63 짹 15 years) had D-dimer testing for various reasons. We defined the D-dimer value more than 0.5mg/L as ���positive���. Results: 1,093 of total patients (53%) had a positive result. The false positive rate for VTE was 95%, and false negative rate for VTE was 0.1%. Significant false positive predictors of positive D-dimer were stroke, heart failure, active infection, post-operation, trauma, bleeding and malignancy (Table). The discriminative value of D-dimer test was assessed by ROC curve analysis. A D-dimer value of 0.68 mg/L on admission was the best cutoff value in predicting the development of VTE with sensitivity, specificity values of 95%, and 57%, respectively (Figure). Conclusion: Many factors are associated with a positive D-dimer test. The effect of these factors on the usefulness of the test should be considered prior to ordering a D-dimer.