D-dimer

D-dimer is a protein fragment produced when a blood clot dissolves in the body. It is a specific indicator of fibrinolysis, the natural process by which the body breaks down clots. Fibrin, a critical protein in clot formation, is cross-linked by Factor XIIIa. When the enzyme plasmin degrades this cross-linked fibrin, D-dimer fragments are released into the bloodstream. Measuring D-dimer levels can help assess the extent of clotting and subsequent clot breakdown activity within the vascular system.