Scoring

Clinical signs and symptoms of DSVT (minimum of leg swelling and pain with palpation of the deep veins).

An alternative diagnosis is less likely than PE.

Heart rate over 100 beats per minute.

Immobilisation for more than 3 days or surgery in the previous 4 weeks.

Previous DVT/PE.

Haemoptysis.

Malignancy (on treatment, treated in the last 6 months, or palliative).