title: An evaluation of rapid D-dimer assays for the exclusion of deep vein thrombosis.
abstract: We evaluated the performance of eight d-assays for the exclusion of deep vein thrombosis (DVT); Biopool AutoDimer, Biopool MiniQuant, bioMèrieux MDA D-Dimer, VIDAS, Dade Behring D-Dimer Plus, Trinity Biotech AMAX, NycoCard D-dimer and IL Test D-Dimer. The assays were evaluated both as stand-alone tests, and in combination with pretest probability (PTP). D-dimer assays and PTP assessment were performed on 410 patients presenting to the emergency department with suspected acute DVT. DVT was diagnosed in 76 of 410 patients (18.5%) by compression ultrasound or other imaging techniques, as required. Receiver operator characteristics analysis established optimum cut-off values and these were compared with manufacturer's cut-off values where provided. As stand-alone tests, the assays varied immensely regarding cut-off value, negative predictive value (NPV 93-100%) and specificity (0-67%). At least one patient with confirmed DVT had a low d-dimer level by each method: to achieve 100% sensitivity it would be necessary to reduce cut-off values to levels below clinical usefulness. When low d-dimer was used in combination with PTP, six of eight methods achieved > or =98% NPV, with a diagnosis of DVT excluded in 16-44% of patients without the requirement for diagnostic imaging. The highly variable diagnostic performance of these d-dimer assays means that some assays are unsuitable for certain diagnostic strategies. However, our data suggest that the combination of sensitive D-dimer assays with an assessment of PTP may be used to exclude a diagnosis of DVT.
authors.affiliation: Department of Haematology, University College London Hospitals NHS Trust, London W1T 4EU, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Gardiner
authors.forename: Coralie
authors.initials: C
authors.lastname: Pennaneac'h
authors.forename: Claire
authors.initials: C
authors.lastname: Walford
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Machin
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Mackie
mesh_terms: D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D020246:Venous Thrombosis / Q000175:diagnosis*
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D