Does this test have other names?
Fragment D-dimer, fibrin degradation fragment
What is this test?
This is a blood test to look for a substance called D-dimer. This test is used to
rule out a blood clot.
D-dimer is a protein fragment from the breakdown of a blood clot. Blood clots generally
start to slowly break down after they are formed, and this process releases D-dimer
into the blood.
Why do I need this test?
You may need this test if your healthcare provider suspects you have a blood clot.
A blood clot that forms in a deep vein is called a deep vein thrombosis (DVT). A DVT
is most commonly found in the legs. If the clot travels to the lungs, it's called
a pulmonary embolism (PE). In the lungs, the clot can cut off the flow of blood. This
is a medical emergency and may cause death.
Symptoms of a blood clot include:
Leg swelling (edema)
Leg pain or soreness
If you have these symptoms, call your healthcare provider.
You may also have a D-dimer test if you have symptoms of a blood clot in the lungs,
If you have these symptoms, call 911 or get emergency help.
People with blood clots often have 1 or more risk factors. These risk factors include:
Major surgery (for example, hip surgery) or injury (for example, a broken leg)
Not being able to move for long periods of time (for instance, from being in the hospital, or
taking long trips by plane or car)
Pregnancy or recent childbirth
Inherited clotting disorder, such as factor V Leiden mutation
You may also need this test to help diagnose and monitor treatment for other conditions.
What other tests might I have along with this test?
You may need more blood tests, including platelet count, fibrinogen, and prothrombin
If your D-dimer test is positive, you will have other tests. You may have the following
imaging tests to look for blood clots:
These tests help your healthcare provider diagnose blood clots in your legs, arms,
lungs, or other parts of the body.
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses
to do the test. Even if your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
An elevated D-dimer level is not normal. It's usually found after a clot has formed
and is in the process of breaking down. If you are having significant formation and
breakdown of a blood clot in your body, your D-dimer may be elevated.
A negative D-dimer test means that a blood clot is highly unlikely.
A positive D-dimer test doesn't mean that you have a clot. There may be other reasons
it is positive. More testing is usually needed.
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Does this test pose any risks?
Taking a blood sample with a needle carries small risks that include bleeding, infection,
bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight
stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Levels may be higher in people with other problems. They include infection, heart
attack (myocardial infarction), liver disease, cancer, and injury.
How do I get ready for this test?
You don't need to prepare for this test.