The present invention discloses a catheter instrument (1000) comprising a needle tip shielding device (100), a needle (303), a needle carrying unit, and a catheter unit, said catheter unit comprising a catheter hub (200) and a catheter (201), and said needle tip shielding device (100) and said catheter hub (200) being separable from one another, wherein said needle tip shielding device (100) is kept in contact with said catheter unit upon withdrawal of said needle (303) via at least one interface surface between said needle tip shielding device (100) and said catheter unit, and wherein said at least one interface surface of said needle tip shielding device (100) being at least partly of a first polymeric material and said at least one interface surface of said catheter unit being at least partly of a second polymeric material.
