D-dimer
D-dimers are the end produducts of fibrin degradation stabilized by crosslinks.
Formation
The thrombus, which was created by the process of hemostasis, is then removed by the fibrinolytic system – plasmin splits the high-molecular polymers of fibrin into fragments of different sizes, the so-called fibrin degradation products (FDP). D-dimers are the smallest degradation products.
Their name is derived from the fact that, in addition to one E subunit, they also contain two D subunits.
Use
D-dimers serve as markers of thromboembolic conditions, which are characterized by increased fibrinolysis and thus an increased concentration of FDP and D-dimers in plasma.
In the diagnosis of deep vein thrombosis, pulmonary embolism a DIC, their determination is important mainly as a negative predictive factor – a negative test result significantly reduces the probability that it is thrombosis, on the contrary, a positive test can be a manifestation of various diseases - e.g. extensive infectious inflammation, myocardial infarction , or pregnancy, conditions after surgical operations, etc. (high sensitivity of the test, but relatively low specificity).
