D-dimer levels and risk of recurrent venous thromboembolism

Blood levels of D-dimer can be used to determine the risk of a second episode of thromboembolism in patients who have already had this medical condition, according to a study of 610 patients. Those with a D-dimer level of 250 nanograms per milliliter or less had a very low risk of a second episode. Those with a D-dimer level of 750 or more had a much greater risk. Thromboembolism occurs when a blood clot forms in a large vein and then travels to another part of the body. Patients with a high risk must take anticoagulant drugs.