D-dimer is a test that measures the tendency of blood to clot inappropriately. The higher the number the greater the risk for conditions such as DVT (deep vein thrombosis), pulmonary embolism, and arterial plaque rupture. Clotting indicates greater risk for heart disease and stroke. D-dimer is done with symptoms of DVT, such as leg pain, tenderness, swelling, discoloration, edema; or symptoms of PE, such as labored breathing, coughing, and lung-related chest pain. Fasting is not required for this test. Take all medications as prescribed.