Check if the patient has any of the following severity criteria:

Systolic blood pressure <100 mm Hg.

Arterial oxygen saturation <90%

Respiratory rate ⩾30 breaths per minute

Pulse ⩾110 beats per minute

Sudden or progressive dyspnea

Other serious complications, constituting admission criteria in and of themselves

Clinically relevant bleeding, high risk of bleeding, or platelets <50 000 mm−3.