Intended for healthcare professionals

Practice Clinical Update

Deep vein thrombosis

BMJ 2018; 360 doi: (Published 22 February 2018) Cite this as: BMJ 2018;360:k351
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Investigating DVT

An approach to symptoms suggestive of lower deep vein thrombosis (DVT)

This article has a correction. Please see:

  1. M J Stubbs, clinical research fellow and haematology registrar1,
  2. Maria Mouyis, consultant rheumatologist2,
  3. Mari Thomas, consultant haematologist1
  1. 1University College London Hospital, London, UK
  2. 2North West London Hospitals NHS Trust, London, UK
  1. Correspondence to M Stubbs m.stubbs{at}

What you need to know

  • Pain, swelling, and redness of the affected limb are common symptoms of deep vein thrombosis (DVT)

  • Assess patients’ clinical risk of DVT using the Wells score

  • Refer urgently patients with suspected DVT for D-dimer test and/or proximal leg ultrasound

  • Anticoagulation to prevent clot extension and embolisation is initiated in secondary care, ideally within four hours of presentation

  • A direct oral anticoagulant is now first line for anticoagulation in patients with DVT not associated with cancer

Deep vein thrombosis (DVT) commonly affects the lower limb, with clot formation beginning in a deep calf vein and propagating proximally.1 It is a common venous thromboembolic (VTE) disorder with an incidence of nearly 1.6 per 1000 inhabitants a year.234 The rate of involvement of particular sites varies: distal veins 40%, popliteal 16%, femoral 20%, common femoral 20%, and iliac veins 4%.1 Certain medical conditions listed in box 1 increase the likelihood of clot formation in the deep veins. Upper limb DVT represents less than 10% of all DVT, and central venous catheters are the main risk factor.7 Venocaval thromboses are rare and are associated with malignancy, compression, and vascular abnormalities.8 This article provides an overview for non-specialists on initial approach to patients with suspected DVT.

Box 1

DVT risk factors56

Transient risk factors

  • Surgery with general anaesthetic (increased if >30 minutes)*

  • Hospitalisation (increased if >3 days with “bed rest”)*

  • Caesarean section*

  • Oestrogen therapy

  • Pregnancy or puerperium

  • Leg injury with reduced mobility for at least three days

Persistent risk factors

  • Active cancer

  • Medical condition with increased risk of recurrent VTE (inflammatory bowel disease, systemic lupus erythematosus)

Unprovoked VTE

  • If the above “Transient” and “Persistent” criteria are not met

  • *10 fold increase in VTE risk


Sources and selection criteria

We searched Medline and Cochrane databases for clinical trials, systematic reviews, and meta-analyses relevant to the diagnosis and management of DVT. Search terms included “deep vein thrombosis,” …

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