D-dimer is a fibrin degradation product

Fibrin degradation product

Fibrin degradation product , also known as fibrin split products, are components of the blood produced by clot degeneration.These are produced by the action of plasmin on deposited fibrin...

 (or FDP), a small protein fragment present in the blood after a blood clot

Thrombus

A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system...

 is degraded by fibrinolysis

Fibrinolysis

Fibrinolysis is a process that prevents blood clots from growing and becoming problematic. This process has two types: primary fibrinolysis and secondary fibrinolysis...

. It is so named because it contains two crosslinked D fragments of the fibrinogen

Fibrinogen

Fibrinogen is a soluble plasma glycoprotein, synthesised by the liver, that is converted by thrombin into fibrin during blood coagulation. This is achieved through processes in the coagulation cascade that activate the zymogen prothrombin to the serine protease thrombin, which is responsible for...

 protein.

D-dimer concentration may be determined by a blood test

Blood test

A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....

 to help diagnose thrombosis

Thrombosis

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...

. Since its introduction in the 1990s, it has become an important test performed in patients suspected of thrombotic disorders.