Analytical performance of the quantitative point-of-care PATHFAST D-dimer assay

In the diagnosis of venous thromboembolism (VTE), the use of point-of-care (POC) D-dimer testing is emerging as a promising alternative to laboratory-based D-dimer assays. These POC devices, easier to use, raise the question of their analytical and clinical performances. We evaluated the analytical performances of the POC Pathfast D-dimer chemiluminescence assay and compared its results with two laboratory-based D-dimer assays: Vidas D-dimer Exclusion II and STA-Liatest D-Di Plus. Within- and between-run imprecision were evaluated using low-and high-level quality control plasma samples and healthy controls and patients’ whole blood. Limit of quantification and linearity were determined according to the Clinical and Laboratory Standards Institute (CLSI). Comparisons were performed using the Passing-Bablok and Bland-Altman analysis, using fresh citrated whole blood and plasma samples collected from 150 consecutive routine samples. The within- and between-run imprecision of the assay did not exceed 4.4% and 5.8%, respectively. Our study found higher D-Dimer results with the Pathfast D-dimer assay (whole blood) than with the Vidas D-dimer Exclusion II and STA-Liatest D-Di Plus assays (plasma) with mean bias of 1.16 and 1.20 μg/mL FEU, respectively. Around the most clinically relevant area (<1 μg/mL FEU), bias was smallest, from 0.07 to 0.15 μg/mL FEU. The Pathfast D-dimer assay is a rapid POC test for determination of D-dimer with good analytical performance. However, these results may be further investigated by a well-designed prospective clinical evaluation in a context of VTE suspicion and appropriate scoring. • The use of point-of-care (POC) D-dimer testing is emerging as a promising alternative to laboratory-based D-dimer assays. • These POC devices raise the question of their analytical and clinical performances and should be evaluated. • The Pathfast D-dimer assay is a rapid POC test for determination of D-dimer with good analytical performance. • These results may be further investigated by a well-designed prospective clinical evaluation in a context of VTE suspicion and appropriate scoring.