A fluid path set for use with an injection device has a single-patient disposable set and a patency check device. A proximal end of the single-patient disposable set is configured for connecting with the injection device. The patency check device has a proximal end configured for connecting with a distal end of the single-patient disposable set and a distal end configured for connecting with a patient fluid delivery device. The patency check device has a body extending between the proximal end and the distal end. The body has a reversibly expandable interior chamber configured for drawing fluid through the patient fluid delivery device during a patency check. The patency check device further has a locking mechanism configured for controlling the volume of the interior chamber during an injection procedure.
