A pre-sterilized fluid sampling syringe is provided which includes a locking vacuum syringe, 3-way valve, check valve and thermoplastic inlet tubing capable of both aseptic welding and direct connections. The syringe is assembled with components and rendered sterile in its packaging. The packaging permits manipulation of the syringe by the user such that at time of use a vacuum can be generated in the syringe barrel by pulling and locking the plunger into a fully withdrawn position. By using the check valve and vacuum feature of the sampling system the user of the device has a means of aseptically flushing and obtaining fluid samples from a desired system, typically a bioreactor or other process used in biotechnology and/or pharmaceutical laboratories and manufacturing operations.