A method and apparatus are provided for automatically detecting the type of replacement fluid loaded by the operator during a therapeutic exchange procedure and to provide a warning alarm if an incorrect fluid is used. After the operator connects the container of replacement fluid to the replacement fluid line of a single-use kit and enters into the controller an identification of the exchange procedure to be performed, the replacement fluid is flowed through a segment of the kit in proximity to a sensor associated with the hardware component that detects the type of fluid flowing through the segment. The controller verifies whether the replacement fluid detected in the segment corresponds to that appropriate for the selected exchange procedure, and notifies the operator in the event that an incorrect replacement fluid has been loaded.