
Fibrin degradation products (FDP) are substances that remain in your bloodstream after your body dissolves a blood clot. Your fibrinolytic (clot-busting) system manages and regulates clot dissolving.
When you cut yourself, the injured blood vessel constricts to stop bleeding and promote healing. This process is called hemostasis. Platelets in your blood gather together and stick to the injury site to form a plug or clot. The formation of the plug or clot is called the clotting cascade.
Fibrin is a protein that aids in clotting. Clotting, also called coagulation, at the wound site produces a mass of fibrin threads called a net. The net remains in place until the cut is healed. As the cut heals, the clotting slows down. Eventually the clot breaks down and dissolves.
When the clot and fibrin net dissolve, fragments of protein are released into the body. These fragments are fibrin degradation products (FDPs). If your body is unable to dissolve a clot, you may have abnormal levels of FDPs.
Blood tests can measure your level of FDPs to see if you have a clotting disorder. The fibrin degradation products test is a specific test that determines the amount of FDPs in your blood. The test is also known as the fibrin split products (FSPs) test, or the fibrin breakdown products test.