Strategies for the safe and effective exclusion and diagnosis of deep veinthrombosis by the sequential use of clinical score, D-dimer testing, and compression ultrasonography

Patients with suspected deep vein thrombosis (DVT) are subjected to leg vei n compression ultrasonography (CUS) that confirms DVT in only 20 to 30% of patients. A positive CUS is consistent with DVT irrespective of clinical sc ore. The sequential use of a simple clinical score assessment, a rapid sens itive enzyme-linked immunosorbent assay (ELISA) D-dimer test and CUS to saf ely exclude DVT is promising. The clinical score is a validated clinical mo del of complaints, signs, and symptoms, on the basis of which a pretest cli nical probability for DVT can be estimated as low, moderate, and high. The safe exclusion of DVT by a rapid sensitive D-dimer test in combination with clinical score or CUS necessitates a negative predictive value of more tha n 99%, The negative predictive value for DVT is determined by the sensitivi ty of the rapid ELISA D-dimer test and the prevalence of DVT in subgroups o f outpatients,vith suspected DVT The prevalence of DVT in outpatients with a low, moderate, and high clinical score varies widely from 3 to 10%, 15 to 30% and more than 70%, respectively. A negative rapid ELISA D-dimer and a low clinical score (prevalence DVT 3 to 5%) will have a very high negative predictive value of more than 99.5% to exclude DVT without the need of CUS testing. A negative ELISA D-dimer test and a first-negative CUS safely excl ude DVT in patients with a moderate clinical score with a negative predicti ve value of more than 99.5%, therefore obviating the need to repeat CUS, Th e use of a rapid ELISA D-dimer testing in patients with a high clinical sco re is not recommended. A negative CUS, a low clinical score, and a positive ELISA D-dimer, even less than 1000 ng/mL exclude DVT with a negative predi ctive value of more than 99%, Patients with a negative CUS, but a positive ELISA D-dimer, and a moderate or high clinical score have a probability of; DVT of 3 to 5% and 20 to 30%, respectively, and are thus candidates for re peated CUS testing. The proposed sequential use of the clinical score asses sment, a rapid ELISA D-dimer test, and CUS will be the most cost-effective diagnostic strategy for DVT because of a significant reduction of CUS exami nations and gain of time for the:patient and physician in charge.