A definitive diagnosis of the presence of a blood clot can be performed at your doctor’s office or hospital setting. Depending on the suspected location of the blood clot and the type, a physician has a number of options at his or her disposal. Among them include:
- Blood tests
- CT scans
How do blood clot diagnostic tests work?
In the case of a suspected pulmonary embolism (PE), your doctor or a physician will start with the physical exam, looking for signs of swelling, tenderness, discoloration or warmth in the legs. Why the legs when the pulmonary embolism is a blood clot found in the lung? Because pulmonary embolisms are commonly caused by a blood clot that has formed in the lower extremities or the thighs, known as a deep vein thrombosis or DVT.
In some cases, the blood clot breaks off from the wall of the blood vessel of the leg and travels upward through the circulatory system. It may ends up lodged in one of the pulmonary or lung blood vessels.
In such cases, a doctor will order numerous tests including chest x-rays or ultrasound. Blood tests may also be recommended in order to determine levels of oxygen and carbon dioxide in the blood. Blood tests also enable the physician to detect presence of D dimer, which is a protein fragment typically found in blood after a blood clot has been dissolved or broken down by the body.
Computed tomography or CT scans may go a step further. In some cases a physician may recommend a computer tomographic angiography (CTPA) - a type of x-ray test that most physicians utilize to diagnose a pulmonary embolism.
One of the most definitive test to determine presence of a pulmonary embolism is a test called a ventilation/perfusion scan, otherwise known as V/Q. This test involves insertion of a catheter into one of the large veins in the groin, and one into an artery that services the lung. A dye is injected into the catheter and will show up on an x-ray. In this way, the doctor can locate the blockage.
Some blood clots that end up in the lungs can damage the heart due to lack of oxygen. In such cases, an echocardiogram may be recommended, otherwise known as a heart ultrasound. The echocardiogram or ECG is not used as a diagnostic test for PE, but it does show if the heart is being affected by the pulmonary embolism.
In order to detect a deep vein thrombosis or DVT, a physician will also begin the diagnostic process through visual examination. One of the most common diagnosis tests for DVT diagnosis is the ultrasound, a technique that utilizes sound waves to create an image of arterial and venous flow in the affected leg.
As with the PE, a D dimer test may also be recommended, as well as venography, which, like the V/Q test, utilizes a dye injected into a vein, enabling an image of the vein to be displayed on an x-ray to show if blood flow has slowed or stopped in the vein.
Treatment options will depend on the testing results.