Thrombosis is the formation of a blood clot, known as a thrombus, within a blood vessel. It prevents blood from flowing normally through the circulatory system. Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in your body, usually in your legs. Venous thrombosis is when the blood clot blocks a vein. Veins carry blood from the body back into the heart. Arterial thrombosis is when the blood clot blocks an artery. Arteries carry oxygen-rich blood away from the heart to the body. Diagnosis of disease is done by given methods , Ultrasound. This test uses sound waves to check the blood flow in your arteries and veins. Blood tests These may include tests to see how well your blood can clot, Venography For this test, a dye is injected into your veins. Then X-rays are taken to show blood flow and look for clots. The dye makes your veins easier to see on the X-rays, MRI, MRA or CT The imaging procedure that is used will depend on the type of blood clot you have and where it is located. To treat blood clots and prevent the damage they cause, doctors use anticoagulants, which are commonly called blood thinners, to decrease the clotting power of the blood and prevent growth of a clot. The most common blood thinners used today are heparin, low molecular weight heparin, and warfarin