BACKGROUND: D-Dimer measurement has been used as a simple, non-invasivetest to rule out thromboembolic phenomena in patients at risk for deep venous thrombosis (DVT) and /or pulmonary embolism (PE). Elevated D-Dimer level caused by tissue injury is believed to show a trendfor gradual decrease to normal within the first three days after trauma. MATERIAL/METHODS: To study theeffect of tissue injury on D-Dimer levels, we conducted a prospective measurement of D-Dimer levels inseverely traumatized, high-risk patients for DVT or PE, starting within 24 hours after admission untildisposition of the patient or to a total of 14 days of hospitalization. Patients were observed clinicallyfor development of thromboembolic phenomena, and were subjected to weekly surveillance using duplex scanof the lower extremities. Additional testing was done if requested by the attending trauma surgeon. RESULTS:A total of 21 patients were enrolled in the study. There were 17 males, and 4 females. Patients had amean age of (42) with a range of (17-79), and a mean ISS score of (20) with a range of (4-50). Sevenpatients completed 3-9 days of testing. Fourteen patients had more than 10 days of testing. Nine patientscompleted 14 days of testing. In all patients, tissue injury resulted in increased levels of D-Dimerabove a threshold (500 ng/ml), below which DVT or PE can be ruled out. The increased levels failed tonormalize even when testing was continued for 14 days. CONCLUSIONS: In our study, the increased D-Dimerlevels induced by tissue injury failed to show a trend of gradual return to normal within three daysafter trauma, as currently believed. This, in our opinion, may eliminate our ability to use D-Dimer testingto rule out DVT or PE in a subset of severely traumatized patients in the early post trauma period.

Keywords: Adolescent, Fibrin Fibrinogen Degradation Products, Pulmonary Embolism, Research Support, Non-U.S. Gov, Time Factors, Venous Thrombosis, Wounds and Injuries