How Is Deep Vein Thrombosis Diagnosed?
Your doctor will diagnose deep vein thrombosis (DVT)
based on your medical history, a physical exam, and the results from tests. He
or she will identify your risk factors and rule out other causes for your
symptoms.
Medical History
To learn about your medical history, your doctor may
ask about:
- Your overall health
- Any prescription medicines you're taking
- Any recent surgeries or injuries you've had
- Whether you've been treated for cancer
Physical Exam
During the physical exam, your doctor will check
your legs for signs of DVT. He or she also will check your blood pressure and
your heart and lungs.
Diagnostic Tests
You may need one or more tests to find out whether
you have DVT. The most common tests used to diagnose DVT are:
- Ultrasound. This is the most common test for
diagnosing deep vein blood clots. It uses sound waves to create pictures of
blood flowing through the arteries and veins in the affected leg.
- A D-dimer test. This test measures a substance in
the blood that's released when a blood clot dissolves. If the test shows high
levels of the substance, you may have a deep vein blood clot. If your test is
normal and you have few risk factors, DVT isn't likely.
- Venography (ve-NOG-ra-fee). This test is used if
ultrasound doesn't provide a clear diagnosis. Dye is injected into a vein, and
then an x ray is taken of the leg. The dye makes the vein visible on the
x ray. The x ray will show whether blood flow is slow in the vein.
This may indicate a blood clot.
Other less common tests used to diagnose DVT include
magnetic resonance imaging (MRI) and computed tomography (CT) scanning. These
tests provide pictures of the inside of the body.
You may need blood tests to check whether you have
an inherited blood clotting disorder that can cause DVT. You may have this type
of disorder if you have repeated blood clots that can't be linked to another
cause, or if you develop a blood clot in an unusual location, such as a vein in
the liver, kidney, or brain.
If your doctor thinks that you have pulmonary
embolism (PE), he or she may order extra tests, such as a ventilation perfusion
scan (V/Q scan). The V/Q scan uses a radioactive material to show how well
oxygen and blood are flowing to all areas of the lungs.
For more about tests used to diagnose PE, see the
Diseases and Conditions Index
Pulmonary
Embolism article. |