A normal range of results for a D-dimer test is less than or equal to 250 neoantigens per milliliter D-dimer units (DDU) or less than or equal to 0.5 micrograms per milliliter Fibrinogen Equivalent Units (FEU), according to Mayo Clinic. These levels are usually reported as negative results.
Doctors generally order D-dimer tests to determine if a person is experiencing blood clots, MedlinePlus reports. A normal or negative test typically means that there are no problematic blood clots present. Positive results, or those higher than the normal range, may indicate blood clots caused by deep vein thrombosis, pulmonary embolism or disseminated intravascular coagulation. Numerous other factors, including pregnancy, advanced age and pre-existing heart or liver disease, can also contribute to positive test results.