The invention relates to a needle assembly (1) comprising:- a needle (2) having a proximal tip (2.1) and a distal tip (2.2)；- a needle hub (3) coupled to the needle (2)；- a body (4) adapted to engage the needle hub (3)； and- a removable needle cap (6) adapted to cover the distal tip (2.2)； characterized by a removable sealing element (5) adapted to seal the proximal tip (2.1), wherein the sealing element (5) is movable to expose the proximal tip (2.1).
