Method for sterilizing a body fluid drainage system for handling a body fluid ex vivo. The body fluid drainage system comprises a chamber. The method comprises the steps providing a container containing a surface protective fluid to be released into the chamber of the body fluid drainage system, subjecting the container to radiation sterilization, inserting the container into the chamber of the body fluid drainage system, and subjecting the chamber containing the container to gas sterilization. A body fluid drainage system for handling a body fluid ex vivo. The body fluid drainage system comprises a chamber. The body fluid drainage system further comprises a container containing a surface protective fluid. The container is arranged to release the surface protective fluid into the chamber. The surface protective fluid is sterilized by radiation sterilization. An outer surface of the container and at least the chamber of the body fluid drainage system is sterilized by gas sterilization.
