What is the purpose of a D-Dimer blood test?

A D-dimer blood test is used to detect blood clots that occur in deep vein thrombosis, stroke and pulmonary embolism, according to Lab Tests Online. Other conditions can cause elevated D-dimer in the blood, so there is a risk of false positives.

The tendency of blood to clot inappropriately and unexpectedly is called hypercoagulability, and it is often the underlying cause of stroke, embolisms or deep vein thrombosis, notes Lab Tests Online. A test to detect D-dimer levels can rule out these conditions, so it is applied to patients with leg swelling or discoloration, chest pain, sudden shortness of breath, or blood in the sputum.