Abstract: An apheresis system includes a chamber configured to receive a centrifuge assembly and a moving loop holder. The moving loop holder includes a loop holder that has a loop connection that is configured to interact with a flexible loop received by the centrifuge assembly. The moving loop holder is configured to move between a first position and a second position, where in the first position, the moving loop holder is a first distance from the centrifuge assembly, and in the second position, the moving loop holder is a second distance from the centrifuge assembly. The centrifuge assembly is prevented from moving from an operating state to a loading state when the moving loop holder is in the first position, and the centrifuge assembly is allowed to move from the operating state to the loading state when the moving loop holder is in the second position.