A disposable set (5) for establishing a fluid connection between a fluid dispensing unit (17) and a dosing device adapted to dispense a fluid into a patients vein. The disposable set comprises a length of tubing (15) having a first (1) and a second (10) tubing part. The first tubing part (1) having a one-way valve (3) which permits a fluid flow from the dispensing unit (17) towards the dosing device and to prevent a backward fluid flow from the dosing device towards the dispensing unit. The first and second tubing part are in fluid connection with each other by means of a releasable connection device (11, 12), which is adapted to permit a back flow from a patient in a released position of the releasable connection device and to prevent a back flow from the patient in a closed position.
