Predictive value of clinical criteria for the diagnosis of deep vein thrombosis

Background. The widespread use of ultrasonography for the diagnosis of deep vein thrombosis (DVT) has led to the overuse of ultrasonography with low diagnostic yield. We conducted this study to investigate the predictive value of clinical features in the diagnosis of DVT and their potential value as clinical guidelines for the use of ultrasonographic testing in the diagnosis of DVT. Methods. The results of lower-extremity duplex ultrasonographic studies and clinical surveys prospectively obtained in 1526 patients suspected of having DVT were analyzed. Results. There were 916 inpatients and 610 outpatients. Acute DVT was found in 16% of the inpatient duplex scans, and in 12% of the outpatient studies (p < 0.05). The incidence of acute DVT was not different between men and women in inpatient or outpatient populations. Acute DVT was found in the left leg in 60% of the outpatient studies, significantly more often (p < 0.001) than in the inpatients (35%). Bilateral DVT was more common (p < 0.05) in the inpatient population (35%) compared with the outpatient population (20%). No difference in the anatomic distribution of thrombosis was found between inpatients and outpatients. The presence of leg symptoms was associated with a significantly higher rate (p < 0.05) of positive studies compared with those patients without leg symptoms in both the inpatient and the outpatient populations. Individual symptoms, risk factors, and physical findings had low positive predictive value and sensitivity for the presence of acute DST on duplex scan. A calf circumference discrepancy of less than 2 cm predicted the absence of DVT in 93% of inpatients and 85% of outpatients. The combination of a calf circumference discrepancy of less than 2 cm with the absence of recent operation, trauma, malignancy, previous history of DVT, or hypercoagulable state predicted the absence of DVT in 92% of the inpatients and 97% of the outpatients. Conclusions. Clinical symptoms, risk factors, and physical findings are poor predictors of the presence of acute DVT on duplex scan. However, absence of a combination of objective clinical factors has high predictive value for the absence of acute DVT on duplex scan. These criteria may be used to establish clinical guidelines to reduce the use of duplex scanning for the diagnosis of DVT.