D-Dimer Test
Reviewed
Also called: fragment D-dimer, fibrin degradation fragment
A D-dimer test looks for D-dimer in blood. D-dimer is a protein fragment (small piece) that's made when a blood clot dissolves in your body.
Specimen: blood
Why this test may be ordered
- To evaluate if you may have a blood clot when you have symptoms of DVT or PE.
- To monitor treatment effectiveness for clotting disorders such as DIC.
Preparation and collection
You don't need any special preparations for a D-dimer test.
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
To understand the results of a D-dimer test, your provider will consider your symptoms, medical history, and the results of other tests.
- Low or normal D-dimer: If your results show low or normal D-dimer levels in the blood, it means you probably don't have a clotting disorder. Limitation: But if you are being treated with blood thinner medicines, they may cause a false negative D-dimer test. This means your test results show that you don't have a clotting disorder, but you really do. Next step: If you have questions about your results, talk to your provider.
- Higher than normal D-dimer: If your results show higher than normal levels of D-dimer, it may be a sign of a clotting disorder. Limitation: High D-dimer levels are not always caused by clotting disorders. A few other possible reasons why you may have high D-dimer levels include pregnancy, heart disease, rheumatoid arthritis, and recent surgery. Being older or immobilized (unable to move) may also cause a high D-dimer level. Next step: Additional tests will be needed to show where the blood clot is located or what type of clotting disorder you have.
- False negative result possible if you are taking blood thinner medicines.
- High D-dimer levels can be caused by pregnancy, heart disease, rheumatoid arthritis, recent surgery, being older, or being immobilized.
What to do next
If your D-dimer test results were not normal, your provider may order one or more imaging tests to find out if you have a clotting disorder. If you have questions about your results, talk to your provider.
- What are the common symptoms of a blood clot?
- Could any of my current medications affect my D-dimer test result?
- What other tests might I need if my D-dimer level is high?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.