Does a negative D-dimer exclude thrombosis?

Abstract

The marked sensitivity of assays of cross-linked fibrin degradation products (XL-FDP) or D-dimer tests for the detection of physiologic fibrinolytic activity has been exploited to exclude the presence of an active thrombotic disorder. For example, as reviewed by Devine in this symposium, a lack of elevation of the concentration of XL-FDP has a negative predictive value of greater than 90% in patients with suspected deep venous thrombosis. Similarly, Deitcher and Eisenberg recently reported that a normal concentration of XL-FDP essentially excluded the presence of gram-negative bacteremia in patients with suspected sepsis.’ The negative predictive value of assays of XL-FDP in plasma from patients with these clinical conditions is dependent on the extent to which increases in intravascular fibrinolytic activity are reflected by increases in the concentration of XL-FDP. While assays of XL-FDP appear to be sensitive and specific for characterizing the intensity of physiologic fibrinolytic activity, it is important to recognize that differences in the immunogenicity of specific XL-FDP, as well as varying intensities of physiologic fibrinolytic response among individuals, may influence the extent to which a low or normal concentration of XL-FDP can be interpreted as excluding thrombosis or increased fibrinolysis.