Evaluation of performance including influence by interfering substances of the Innovance D-dimer assay on the Sysmex coagulation analyzer.

Abstract

D-dimer is formed during activation of the coagulation system and is commonly assayed in order to diagnose disseminated intravascular coagulation, deep vein thrombosis, and pulmonary embolism. Enzyme-linked immunosorbent assay has been validated as the reference method, but it is a time-consuming procedure. The objective of this study was to evaluate a new immunoturbidimetric, particle-enhanced, Innovance(®) D-dimer immunoassay. A total of 129 plasma samples from apparently healthy individuals and 298 samples from patients were collected for linearity, precision, and correlation studies. Testing the precision of low- and high-controls yielded CV values of 2.08% and 1.76%, respectively. The central 95% non-parametric reference interval estimated from healthy controls was 0.093-0.68 mg/L Fibrinogen Equivalent Units (FEU; median, 0.26 mg/L FEU). Comparison analysis yielded acceptable correlation with the STA Liatest(®) D-dimer assay (R(2) = 0.9471). At a cut-off level of <0.5 mg/L FEU, the sensitivity and specificity indices of the Innovance D-dimer assay were 99.7% and 89.1%, respectively. Thus the Innovance D-dimer method showed acceptable precision and linearity, and the assay results showed acceptable correlation with the STA Liatest D-dimer method. The Innovance method was relatively unaffected by potential interfering substances such as bilirubin and hemoglobin. In conclusion, the Innovance D-dimer assay is suitable for monitoring D-dimer concentrations in various clinical conditions and should be useful in clinical laboratories.