View source for Deep vein thrombosis diagnostic approach

'''Editors-in-Chief:''' [[C. Michael Gibson, M.S., M.D.]]  '''Associate Editor-In-Chief''': [[User:Ujjwal Rastogi|Ujjwal Rastogi, MBBS]] [mailto:urastogi@perfuse.org]; [[User:Kashish Goel|Kashish Goel, M.D.]]

{{Deep vein thrombosis}}

==Overview==
A number of invasive (venography) and non-invasive tests (impedance plethysmography, compression ultrasonography, D-dimer testing) are available for diagnosis. Compression ultrasonography is the noninvasive diagnosis of choice for patients with a first episode of suspected DVT. 

In a patient population with high prevalence of [[VTE]], a negative [[D-dimer]] assay may be insufficient to rule out DVT as a single test, and moreover not all D-dimer assays are validated for this. However, a D-dimer level <500 ng/mL by ELISA along  with a low clinical probability ([[Deep vein thrombosis diagnosis#Wells score|Wells score]]) or other negative non-invasive tests may be useful in excluding DVT, without doing ultrasound. 

Compression ultrasonography has a positive predictive value of 94 percent (95% CI: 87-98 percent). If the clinical suspicion of DVT is high even after a negative CUS, a repeat study should be done within a week. Complete lower extremity ultrasonography may eliminate the need for repeat testing, but a positive CUS demands user expertise, and requires specialized instrumentation. The algorithm below presents a possible diagnostic approach.

[[Image: DVT_diagnosis.jpg]]


CUS stands for Compression Ultrasonography; [[D-dimer]] is the highly sensitive assay.
Clinical judgement and local availability should be considered in patients with moderate probability of [[DVT]]. CUS may be preferred in patients with comorbid conditions associated with elevated D-dimer levels. 

Adapted from ACCP guidelines<ref name="pmid22315267">{{cite journal |author=Bates SM, Jaeschke R, Stevens SM, ''et al.'' |title=Diagnosis of DVT: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines |journal=Chest |volume=141 |issue=2 Suppl |pages=e351S–418S |year=2012 |month=February |pmid=22315267 |doi=10.1378/chest.11-2299 |url=}}</ref>.

==Considerations==
* Whole-leg ultrasound may be preferred in those who have severe symptoms of calf DVT or are unable to come for serial testing.
* CT scan venography, MR venography, or MR direct thrombus imaging may be used in those patients in whom ultrasound is not practical (leg cast, excessive edema) or non-diagnostic.

==References==
{{reflist|2}}

[[Category:Hematology]]
[[Category:Pulmonology]]
[[Category:Cardiology]]
[[Category:Emergency medicine]]
[[Category:Mature chapter]]

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