D-Dimer

D-dimer is a fibrin degradation product that indicates recent clot formation and breakdown. This biomarker uses fibrinogen equivalent units (FEU); D-dimer units (DDU) are a different reporting basis with a different reference range. Elevated levels can suggest thrombotic events (DVT, PE), inflammation, or infection. D-dimer is highly sensitive but not specific for thrombosis. It is commonly used to rule out blood clots when levels are normal. Chronically elevated levels may reflect ongoing coagulation activation and inflammation.