D-Dimer is utilised in the diagnosis of thromboembolic diseases. Deep venous thrombosis and pulmonary embolism can be diagnosed using pulmonary angiography, with accurate results. However this is costly, invasive, and not widely available. D-Dimer levels are nearly always elevated in cases of pulmonary embolism. However,elevated levels can also be from various other causes. Therefore the D-Dimer test is generally used to rule out pulmonary embolism. A normal D-Dimer level below 500µg/L allows the exclusion of pulmonary embolism.