D-Dimer Test

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. D-dimer isn't usually found in your blood unless your body is making or breaking up blood clots.

A blood clot is a mass of blood that forms when platelets, proteins, and cells in the blood stick together. When you get hurt, your body forms a blood clot to stop the bleeding. 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 injury, or they don't dissolve when they should. These disorders can be serious and even life-threatening.

Why this test is done

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 in your leg include:

• Leg pain or tenderness
• Leg swelling
• Redness or darkening of the skin on the leg
• Skin that feels warm

Symptoms of PE include:

• Trouble breathing
• Cough
• Chest pain
• Rapid heartbeat and breathing

Many people do not have any symptoms of PE.

Both DVT and PE require quick medical treatment. If you have DVT symptoms and are not in a health care setting, call your health care provider. If you have symptoms of PE, seek immediate medical attention.

How to prepare

You don't need any special preparations for a D-dimer test.

Sample type

Blood

Other names for this test

fragment D-dimer, fibrin degradation fragment