This document provides information about assessing a patient for deep vein thrombosis (DVT). It lists questions to ask the patient about risk factors for DVT like recent surgery, estrogen use, family history of clotting issues, and immobility from travel or injury. It describes performing a physical exam including Homan's sign and using the Wells Rule clinical decision tool to evaluate the likelihood of DVT based on symptoms and risk factors. A positive Homan's sign or Wells Rule score over 1 would indicate higher risk of DVT warranting ultrasound referral.