Pathology: Blood or qi deficiency. This is seen in cases of deficiencies and failure of Qi and blood. It can also be seen in disharmonies of the even emotions, weakness in Yang Qi, internal damage to jing, and penetration of dampness.
Testing for venous blood clots. Venous blood clots may be detected in a variety of ways, though ultrasound is most commonly used. Occasionally, the patient's size and shape limit the ability for ultrasound to provide a definitive answer. Venography is an alternative test to look for a clot.
Your doctor may request a blood test prior to the procedure to determine how long it takes your blood to clot. Other blood tests may be done as well. Tell the doctor if you have heart valve disease, a congenital heart condition, or a history of endocarditis (infection of the heart valves).