Your vascular laboratory has 38 lower extremity venous duple…
Your vascular laboratory has 38 lower extremity venous duplex exams that had a subsequent venogram for a variety of reasons. Of these, both tests documented venous disease in 22 extremities and ruled out venous disease in 10. In 4 cases, the venous imaging study was considered normal while venography documented disease. There were 2 situations where the duplex study was interpreted as abnormal, but no disease was evident on venography. What is the negative predictive value?