Performance of the automated and rapid STA Liatest D-dimer on the STA-R analyzer

Abstract

Objective The aim of the present study was to investigate the accuracy indices of the new automated and rapid microlatex D-dimer assay, STA Liatest D-Di, on the STA-R analyzer and to compare it with established D-dimer assays. Methods D-dimer testing has been performed in 103 consecutive outpatients with suspected deep venous thrombosis (DVT). Diagnosis of DVT was established by contrast venography or color-coded duplex ultrasonography. D-dimers plasma concentrations were measured with the STA Liatest D-Di on the STA-R coagulation analyzer, with a reference ELISA technique (Asserachrom®), with an automated quantitative latex-based immunoassay (Tinaquant®) and with the VIDAS® D-dimer test. Results In total, 103 eligible outpatients entered the current study and DVT was detected in 46 patients (44.6%). Two duplicate D-dimer measurement with the STA Liatest D-Di revealed excellent correlation ( r S=0.996) and almost identical sensitivity (each 98%), specificity (49% and 50%), negative predictive value (NPV; each 97%), positive predictive value (PPV; 61% and 62%) and exclusion rate (27% and 28%), respectively. Comparison of the STA Liatest D-Di with the other D-dimer tests revealed highly significant correlations ( r S=0.951–0.979), highly comparable regression and excellent agreement in clinical interpretation of the test results (kappa coefficients 0.812–0.856). Moreover, sensitivity, specificity, NPV, PPV and exclusion rate at a cut-off level of 500 ng/ml were in the same range for the STA Liatest D-Di when compared with the other D-dimer tests. Conclusion The Liatest D-Di performed on the coagulation analyzer STA-R compares favorable with the VIDAS®, Tinaquant® and Asserachrom® D-dimer tests and is suitable for the safe exclusion of DVT in symptomatic outpatients. The test can be included in an algorithm for DVT diagnosis including other diagnostic tools.