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.
Blood clotting is an important process that prevents you from losing too much blood when you are injured. Normally, your body will dissolve the clot once your injury has healed. With a blood clotting disorder, clots can form when you don’t have an obvious injury or don’t dissolve when they should. These conditions can be very serious and even life-threatening. A D-dimer test can show if you have one of these conditions.
Other names: fragment D-dimer, fibrin degradation fragment
A D-dimer test is used to find out if you have a blood clotting disorder. These disorders include:
You may need this test if you have symptoms of a blood clotting disorder, such as deep vein thrombosis (DVT) or a pulmonary embolism (PE).
Symptoms of DVT include:
Symptoms of PE include:
This test is often done in an emergency room or other health care setting. If you have DVT symptoms and are not in a health care setting, call your health care provider. If you have symptoms of PE, call 911 or seek immediate medical attention.
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.
You don’t need any special preparations for a D-dimer test.
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.
If your results show low or normal D-dimer levels in the blood, it means you probably don’t have a clotting disorder.
If your results show higher than normal levels of D-dimer, it may mean you have a clotting disorder. But it cannot show where the clot is located or what type of clotting disorder you have. Also, high D-dimer levels are not always caused by clotting problems. Other conditions that can cause high D-dimer levels include pregnancy, heart disease, and recent surgery. If your D-dimer results were not normal, your provider will probably order more tests to make a diagnosis.