title: Clinical evaluation of eight different D-dimer tests for the exclusion of deep venous thrombosis in primary care patients.
abstract: D-dimer tests are an essential element in the diagnostic work-up of deep venous thrombosis (DVT). However, the poor standardization amongst assays necessitates clinical validation before implementation in daily practice. We therefore evaluated the analytical and diagnostic performance of eight D-dimer tests in a representative group of 290 prospectively identified consecutive primary care patients with suspected DVT. Seven quantitative D-dimer assays, and a qualitative test, Simplify, were evaluated. Correlation between assays was generally poor and several assays showed a significant bias in the method comparison. Nevertheless, the Vidas D-dimer, Innovance D-dimer (CA1500 and BCS), Pathfast D-dimer, and HemosIL HS500 (ACL TOP), all displayed 100% (95% CI: 85-100%) sensitivity. Tina-quant (Modular), AQT90 D-dimer, and Liatest (STA(®)) D-dimer tests showed a slightly lower sensitivity of 95% (78-100%). and the Simplify test reached a sensitivity of 91% (72-99%) that was further improved in combination with a clinical decision rule to 95% (76-100%). In concert with the low (8.2%) prevalence of proximal DVT, diagnosed by compression ultrasonography, in our study, all test reached a negative predictive value (NPV) of at least 99%. The user friendliness of the assays differed mainly by stability of reagents, calibration frequency, time required to obtain a test result and costs of a test. In conclusion, despite considerable analytical differences, in our low-risk population all tests evaluated displayed an excellent NPV. In combination with a validated clinical decision rule to identify low-risk patients, even a straightforward POC solution could safely and cost-efficiently rule out DVT.
authors.affiliation: Certe - Department of Clinical Chemistry , Groningen.
authors.forename: Rob F M
authors.initials: RF
authors.lastname: Oude Elferink
authors.forename: Annemarieke E
authors.initials: AE
authors.lastname: Loot
authors.forename: Chantal G J
authors.initials: CG
authors.lastname: Van De Klashorst
authors.forename: Marieke
authors.initials: M
authors.lastname: Hulsebos-Huygen
authors.forename: Margriet
authors.initials: M
authors.lastname: Piersma-Wichers
authors.forename: Ruud
authors.initials: R
authors.lastname: Oudega
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001774:Blood Chemical Analysis / Q000592:standards; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011320:Primary Health Care; D012015:Reference Standards; D020246:Venous Thrombosis / Q000097:blood / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D
keywords: Venous thrombosis; clinical laboratory techniques; fibrin fibrinogen degradation products; humans; immunoassay; point-of-care systems; predictive value of tests; primary health care