A deep vein thrombosis is a blood clot that develops in a deep vein, usually in the leg. DVT is a very common condition, which affects about 2 million Americans every year. Certain genetic risk factors as well as acquired risk factors make a DVT more likely to occur. If a deep vein thrombosis is suspected, tests will be needed to confirm the diagnosis. But DVT can lead to a life threatening condition, called Pulmonary Embolism, a blood clot in the lungs. See how DVT can be detected and treated early, and how Pulmonary Embolism can be avoided.