Performance of a new fibrin monomer assay to exclude deep vein thrombosis in symptomatic outpatients

In this study we prospectively assessed the reliability of a new fibrin mon omer assay in 106 outpatients with clinically suspected deep venous thrombo sis of the lower limb. According to the results of the objective tests and using different cut-off points we calculated the sensitivity, specificity a nd negative predictive value of the fibrin monomer assay. The prevalence of deep vein thrombosis was 44.3% (31.1% proximal, 13.2% distal). Using a cut -off level of plasma fibrin monomer of 3.5 mu g/ml, a sensitivity, specific ity and negative predictive value of 100% (95% CI: 94-100%), 35.6% (95% CI: 23-48%) and 100% (95% CI: 86-100%). respectively, were obtained. The exclu sion rate was 19.8% (95% CI: 12-27%) of all referred patients. These accura cy indices compared favourably with the respective results of a routine D-d imer ELISA used for comparison. Conclusion: This; new fibrin monomer assay appears to be a reliable method for the exclusion of deep vein thrombosis i n symptomatic outpatients.