Table of Contents
ISRN Radiology
Volume 2014 (2014), Article ID 519875, 5 pages
Research Article

Evaluating the Use of a Negative D-Dimer and Modified Low Wells Score in Excluding above Knee Deep Venous Thrombosis in an Outpatient Population, Assessing Need for Diagnostic Ultrasound

1Department of Radiology, Royal London Hospital, Whitechapel, London E1 1BB, UK
2Fast Response Team, Royal London Hospital, Whitechapel, London E1 1BB, UK
3Department of Haematology, Royal London Hospital, Whitechapel, London E1 1BB, UK

Received 9 January 2014; Accepted 24 February 2014; Published 9 March 2014

Academic Editors: M. G. Andreassi, U. Bozlar, and M. F. Giannoni

Copyright © 2014 Maryam Rahiminejad et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Aims. Colour doppler ultrasonography (CDUS) is widely used in the diagnosis of deep venous thrombosis (DVT); however, the number of scans positive for above knee DVT is low. The present study evaluates the reliability of the D-dimer test combined with a clinical probability score (Wells score) in ruling out an above knee DVT and identifying patients who do not need a CDUS. Materials and Method. This study is a retrospective audit and reaudit of a total of 816 outpatients presenting with suspected lower limb DVT from March 2009 to March 2010 and from September 2011 to February 2012. Following the initial audit, a revised clinical diagnostic pathway was implemented. Results. In our initial audit, seven patients (4.9%) with a negative D-dimer and a low Wells score had a DVT. On review, all seven had a risk factor identified that was not included in the Wells score. No patient with negative D-dimer and low Wells score with no extra clinical risk factor had a DVT on CDUS (negative predictive value 100%). A reaudit confirmed adherence to our revised clinical diagnostic pathway. Conclusions. A negative D-dimer together with a low Wells score and no risk factors effectively excludes a lower limb DVT and an ultrasound is unnecessary in these patients.