A medical connector (18) has a visual signal (67) formed by a coloured screen-applied band arranged on a bolt (63).In a correct engaged position of the bolt (63) with an external element, thesignal is visible. In an incorrect engaged position, thepart of the bolt (63) bearing the signal is lowered, so that the signal ishidden from view, providing an indication of a faulty situation.The medical connector serves to connect the end of a dialysate supply tube toan inlet port of a dialyser.
