The use at a rapid D-dimer blood test in the diagnostic work-up for pulmonary embolism: A management study

Background D-dimer assays have a potential to rule out pulmonary embolism i n case of a normal test result. We studied the clinical utility of incorpor ating the SimpliRED D-dimer test result and clinical probability in the rou tine diagnostic work-up of patients with suspected acute pulmonary embolism . Methods. In a prospective management study 245 consecutive patients, hosp italised as well as outpatients, were included. A SimpliRED D-direr test an d perfusion/(ventilation) scintigraphy were obtained in all patients, where as clinical probability was determined in the subgroup of patients with a n on-diagnostic scan and normal D-dimer result. A diagnostic algorithm determ ined the necessity for further testing and decisions about treatment. All p atients were followed up for 3 months. Results. In 54 patients (22%) with a normal lung scan and 50 patients (21%) with a high probability lung scan, antithrombotic therapy was withheld or started respectively, irrespective o f the D-dimer result. A non-diagnostic lung scan was found in 137 (56%) pat ients, of whom 70 patients had an abnormal D-dimer test, in wham further te sting was ordered. Of the remaining 67 patients with a non-diagnostic lung scan and normal D-dimer test 8 patients had a high clinical probability, an d the subsequent ultrasonography and pulmonary angiography yielded pulmonar y emboli in 1 patient. In the remaining 66 patients, pulmonary embolism was considered to be absent and antithrombotic treatment was stopped/withheld. During follow-up of these patients only one patient experienced a possible venous thromboembolic event (failure rate 1.5%; 95% CT 0-8%). The SimpliRE D D-dimer was normal in 6 of 61 patients with proven pulmonary embolism (se nsitivity 90%; 95% CI 80-96%) Conclusion. Our findings suggest that it is s afe to withhold anticoagulant therapy in those patients with a non-diagnost ic lung scan, a normal SimpliRED D-dimer test result, and without a high cl inical probability. This results in a substantial decreased need for ultras onography and pulmonary angiography. The SimpliRED should not be used in is olation to exclude pulmonary embolism.