Validation Study for Use of an Algorithm for the Diagnosis of Deep Vein Thrombosis in Out-patients

Abstract

In a previous study we demonstrated that the use of an algorithm can decrease unnecessary emergency venous duplex evaluations (VDE) in out-patients and increase the percentage of positive yields. The present study was undertaken to validate the safety of following such an algorithm. During a six month period we suspended the application of the algorithm and performed VDE on all requests for out-patients. A total of 94 requests were received from the Emergency Department and all were honored. Of the 94 out-patients who underwent emergency VDE for deep vein thrombosis (DVT), eleven were positive for DVT (11.8%) and 83 were negative (88.2%). Had the algorithm been applied for patients screening, all the 11 positive studies would have gone to emergency VDE (100%). 10 patients had proximal DVT and 1 had isolated peroneal DVT. The application of an algorithm for inclusion/exclusion of out-patients for emergency VDE is a safe and effective means for limiting emergency access to the non-invasive vascular laboratory.