Clinical tool for health professionals

Wells score for DVT

The two-level Wells score estimates the clinical probability of a deep vein thrombosis. Use it with a D-dimer and proximal leg ultrasound, not instead of them.

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Our centres do not manage suspected acute DVT or pulmonary embolism. Patients with a likely DVT need same-day imaging and, if imaging is delayed, interim anticoagulation: refer to an emergency department or your usual acute pathway. Send any patient with chest pain, breathlessness or haemoptysis for urgent assessment of pulmonary embolism.
Clinical features

Tick everything that applies to the symptomatic leg.

D-dimer and imaging (optional)

Add these to see the next step in the NICE NG158 pathway.

Using the score

  • 2 or more: DVT likely. NICE NG158 advises a proximal leg vein ultrasound within 4 hours. If that is not possible, do a D-dimer and give interim therapeutic anticoagulation, with the scan within 24 hours.
  • 1 or less: DVT unlikely. Do a D-dimer, with the result within 4 hours (if that is not possible, give interim therapeutic anticoagulation while waiting). If it is positive, arrange a proximal leg ultrasound within 4 hours, or interim anticoagulation and a scan within 24 hours. If it is negative, consider an alternative diagnosis.
  • After a negative scan in a patient whose score is 2 or more, NICE advises a D-dimer if not already done; if it is positive, stop interim anticoagulation and repeat the scan 6 to 8 days later.
  • The score was developed in outpatients. It performs less well in inpatients, in pregnancy (where it has not been validated) and in patients with previous DVT on the same side.

After the acute episode

We see patients with post-thrombotic symptoms, recurrent superficial thrombophlebitis and varicose veins after a DVT. Referral details are on the For doctors page.

Sources

  1. Wells PS, Anderson DR, Rodger M, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med. 2003;349:1227–35.
  2. National Institute for Health and Care Excellence. Venous thromboembolic diseases: diagnosis, management and thrombophilia testing (NG158). 2020, with later updates.
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