D-dimer is a protein fragment produced when blood clots dissolve in the body. It is a biomarker that is used to diagnose and monitor conditions related to blood clotting and thrombosis, which is the formation of blood clots in blood vessels.
When a blood clot forms in the body, it triggers a complex process known as coagulation, which involves the activation of blood proteins called clotting factors. As the clotting factors interact, they eventually form a fibrin clot, which is a mesh of protein fibers that help to stop bleeding. As the clotting process continues, the body also produces other substances, including D-dimer, which helps to dissolve the clot when it is no longer needed.
The presence of D-dimer in the blood is a sign that the body has undergone recent clotting activity, as it is produced when a clot is broken down. Therefore, elevated levels of D-dimer may indicate the presence of blood clots or thrombosis in the body. D-dimer tests are often used to diagnose and monitor conditions such as deep vein thrombosis, pulmonary embolism, disseminated intravascular coagulation (DIC), and stroke.
However, it is important to note that D-dimer levels may also be elevated in other conditions, such as inflammation, infection, and cancer. Therefore, a D-dimer test is not a definitive diagnostic tool for thrombotic disorders, and it should be interpreted in conjunction with other clinical and laboratory findings.