Diagnostic accuracy of deep vein thrombosis is increased by analysis using combined optimal cut-off values of postoperative plasma D-dimer levels

The present study aimed to evaluate the accuracy of analysis using optimal cut-off values of plasma D-dimer levels in the diagnosis of deep vein thrombosis (DVT). A total of 175 orthopedic patients with DVT and 162 patients without DVT were included in the study. Ultrasonic color Doppler imaging was performed on lower limb veins prior to and following orthopedic surgery in order to determine the types of orthopedic conditions that were present. An enzyme-linked fluorescent assay was performed to detect the expression levels of D-dimer in plasma, and receiver operating characteristic analysis was performed to predict the occurrence of DVT on the basis of the expression levels of D-dimer. After surgery, the expression levels of D-dimer in the plasma of DVT patients were significantly higher in comparison with those in orthopedic patients without DVT (P<0.05). When the patients were divided into subgroups according to the underlying orthopedic condition, the expression levels of D-dimer in the plasma of each subgroup were higher 1 day after orthopedic surgery in comparison to those prior to surgery (P<0.05). The diagnostic accuracy achieved using combined optimal cut-off values at 1 and 3 days post-surgery was significantly higher than the accuracy when using a single optimal cut-off value (P<0.05). In conclusion, detection of D-dimer expression levels at 1 day post-orthopedic surgery may be important in predicting DVT. In addition, the diagnostic accuracy of DVT is significantly increased by analysis using combined optimal cut-off values of D-dimer plasma expression levels.