D-dimer is derived from the breakdown of fibrin by plasmin and D-dimer test is used to evaluate fibrin degradation. Blood sample can be either serum or plasma. Latex or polystyrene microparticles coated with monoclonal antibody to D-dimer are mixed with patient’s sample and observed for microparticle agglutination. As the particle is small, turbidometric endpoint can be determined in automated instruments. D-dimer and FDPs are raised in disseminated intravascular coagulation, intravascular thrombosis (myocardial infarction, stroke, venous thrombosis, pulmonary embolism), and during postoperative period or following trauma. D-dimer test is commonly used for exclusion of thrombosis and thrombotic tendencies.