Extracorporeal membrane oxygenation (ECMO) is a type of circulatory life support for patients with severe lung failure. The use of ECMO has increased worldwide since the pandemic of H1N1 in 2009 and more recently SARS-CoV-2 in 2020 both of which caused severe respiratory failure. ECMO patients experience both increased risk of bleeding and thrombosis. This is due to the pathological insult that damages the lungs, the ECMO circuit, coagulopathy, inflammation and anticoagulation. ECMO presents unique demands on the coagulation laboratory both in tests required to manage the patients and result interpretation. This is a personal opinion of 20 years ECMO experience as a clinical scientist and a short current review of the literature. It will focus on the laboratory coagulation tests used to manage ECMO patients, including different anticoagulants used, testing frequency and interpretation of the results.