This study explores the sterility and function of pre-primed extracorporeal membrane oxygenation (ECMO) circuits in a clinical setting. Conducted at Sahlgrenska University Hospital, the study assessed 107 ECMO circuits between 2019 and 2021, analyzing sterility through culture tests and oxygenator function through parameters like sweep gas flow and FiO2. Results indicated minimal bacterial growth and no significant impact of wet priming on oxygenator function, suggesting pre-priming is safe and effective for rapid ECMO initiation.