A disposable medical probe for detecting a leak of physiological fluid comprising a support layer, a conductive layer on top of the support layer, the conductive layer comprising two conducting electrodes both placed exclusively on each side of a longitudinal axis, the conductive layer defining two zones: a proximal zone with two proximal electrode parts being placed parallel to each other and being spaced apart by a constant distance d, and a distal zone with two distal electrode parts being spaced apart from each other by a gap e greater than said distance d, where the distal zone of the electrodes defines an increase in the gap between the distal parts of the electrodes, followed by a decrease in the gap between the distal parts of the electrodes.