what does the d dimer test show
D-dimer is normally undetectable in the blood and is produced only after a clot has formed and is in the process of being broken down. When there is significant formation and break down of blood clots in the body, the D-dimer blood level can rise. The D-dimer test measures the level in the blood. For a person who is at low or intermediate risk for thrombosis and/or thrombotic embolism, the strength of the D-dimer test is in its negative predictive value in a hospital emergency room setting. That means that a negative D-dimer test indicates that it is highly unlikely that a thrombus is present.