Abstract: The present invention discloses a technique for determining a position of a distal end of a probe relative to a blood vessel. The method comprises receiving a first pressure pattern comprising a plurality of pressure values being indicative of a pressure of a fluid when the distal end of the probe is located inside the blood vessel, processing the first pressure pattern, and determining at least one adaptive threshold and/or a tendency indication. The adaptive threshold is indicative of a transition from a first position state to a second position state, or vice versa. The tendency indication is indicative of a certain trend of the pressure pattern. The first position state defines an in-blood vessel condition in which the distal end of the probe is located inside the blood vessel and the second position state defines at least one exit condition in which the distal end of the probe is located at least partially outside the blood vessel.