Thrombosis is increasingly emerging as a marker of severe coronavirus with physicians reporting not only respiratory failure but coagulopathy. Interim guidance from the International Society on Thrombosis and Haemostasis advises measuring D-dimer, prothrombin time, platelet counts and fibrinogin. The guidance also recommends using prophylactic doses of LMWH unless contraindicated in all hospitalized covid patients, including those not in the ICU. But some experts think prophylactic dosing may be too low, and some facilities are starting anticoagulation in covid patients with a D-dimer of more than 1,500 ng/mL and fibrinogen higher than 800 mg/mL. While some experts see advantages to using IV heparin in covid patients, other hospitals are instead choosing to use DOACs to limit the number of times nurses have to enter patients' rooms.