Elevated D-dimer levels most directly indicate which process?

Elevated D-dimer levels most directly indicate which process?

• A. Fibrinogen formation
• B. Fibrin cross-linking and degradation
• C. Platelet aggregation
• D. Vessel inflammation

Answer: (B)

D-dimer directly reflects the breakdown of cross-linked fibrin after coagulation. It is a degradation product produced when plasmin cleaves fibrin threads that have been stabilized by factor XIII cross-linking. So, an elevated D-dimer indicates that both fibrin formation with cross-linking occurred and was subsequently degraded by fibrinolysis. This is distinct from fibrinogen formation (upstream to make fibrin), platelet aggregation (a primary hemostasis event), or vessel inflammation (which can accompany many conditions but does not by itself yield the D-dimer fragment).

D-dimer directly reflects the breakdown of cross-linked fibrin after coagulation. It is a degradation product produced when plasmin cleaves fibrin threads that have been stabilized by factor XIII cross-linking. So, an elevated D-dimer indicates that both fibrin formation with cross-linking occurred and was subsequently degraded by fibrinolysis. This is distinct from fibrinogen formation (upstream to make fibrin), platelet aggregation (a primary hemostasis event), or vessel inflammation (which can accompany many conditions but does not by itself yield the D-dimer fragment).