D-dimer is a blood test that helps detect the presence of blood clots in the body. When a wound causes bleeding, the body forms protein fibers called fibrin to create a clot and stop the bleeding. As the wound heals, an enzyme called plasmin breaks down the clot into small fragments, including D-dimer. High levels of D-dimer may indicate an increased risk of blood clotting in the body.
Doctors order a D-dimer test when suspecting conditions such as deep vein thrombosis, pulmonary embolism, disseminated intravascular coagulation, or stroke. Test results can show whether D-dimer levels are normal, low (negative), or high (positive). A positive result suggests the presence of a blood clot, while a negative result indicates the absence of a clot. Additional tests may be needed to locate the specific clot in the body.
It is important to note that high D-dimer levels can also be caused by conditions other than blood clots, such as pregnancy, heart disease, recent surgery, trauma, or infection. These false positives can complicate the interpretation of test results. Therefore, additional testing and imaging may be necessary to confirm a diagnosis accurately.