title: 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.
abstract: 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.
authors: Department of Radiology, Royal London Hospital, Whitechapel, London E1 1BB, UK.
authors: Maryam
authors: 0000-0002-9219-2227
authors: M
authors: Rahiminejad
authors: Department of Radiology, Royal London Hospital, Whitechapel, London E1 1BB, UK.
authors: Anshul
authors: A
authors: Rastogi
authors: Department of Radiology, Royal London Hospital, Whitechapel, London E1 1BB, UK.
authors: Shirish
authors: S
authors: Prabhudesai
authors: Fast Response Team, Royal London Hospital, Whitechapel, London E1 1BB, UK.
authors: David
authors: D
authors: Mcclinton
authors: Department of Haematology, Royal London Hospital, Whitechapel, London E1 1BB, UK.
authors: Peter
authors: P
authors: MacCallum
authors: Department of Haematology, Royal London Hospital, Whitechapel, London E1 1BB, UK.
authors: Sean
authors: S
authors: Platton
authors: Department of Radiology, Royal London Hospital, Whitechapel, London E1 1BB, UK.
authors: Emma
authors: E
authors: Friedman