D-dimer is a degradation product of cross-linked fibrin. A normal level of d-dimer is typically less than 500 ng/mL. In a patient with pulmonary embolism (PE), deep venous thrombosis (DVT), or other clot burden, elevated d-dimer levels reflect the body’s endogenous fibrinolysis. Inaddition, d-dimer levels may also be raised in myocardial infarction, pneumonia, sepsis, and cancer; during the second and third trimesters of pregnancy; and after surgery. Elevated d-dimer levels may persist up to 3 months after surgery.