A new pretest probability score for diagnosis of lower limb deep vein thrombosis in unselected population of outpatients and inpatients

Abstract

Objective To develop a new pretest probability score for deep vein thrombosis (DVT) in unselected population of outpatients and inpatients. Methods The new score was developed using independent factors from 500 patients clinically suspected of leg DVT. The new score was validated in a second group of 315 patients. Results The score consists of four components: unilateral leg pain, confinement to bed, calf enlargement >3 cm compared with the other side, and previous venous thromboembolism. A score ≥2 indicated a high probability while a score <2 indicated low probability. The sensitivity and specificity of the new score were 71.60% and 79.49%, respectively. The area under the receiver operating characteristic curve for the new score was 0.79. The combination of a new score <2 and D-dimer level <500 µg/L had a negative predictive value of 96.43%. Conclusions Our new score was valid in an unselected population of outpatients and inpatients.