Blood sampling assembly with a retractable needle

The present invention relates to devices for obtaining blood samples from a patient, typically for diagnostic testing. More particularly, the invention relates a blood sampling assembly with a retractable needle to protect the health care worker from being inadvertently pricked by the needle after the blood withdrawal operation. The blood sampling assembly includes a retractable double-ended needle so that a vial may be passed through an opposed end of the needle to obtain a blood sample. The assembly includes a hollow cylinder including circumferentially spaced seat tabs which allow a needle seat and the needle supported thereon to be released upon rotation of tube with respect to hollow cylinder. The extractor assembly includes a stopper for maintaining a vacuum within tube to withdraw the needle to a retracted position within the tube upon rotation of the tube, the end cap, and the stopper retainer. A stopper tab positioner rotationally connects the stopper to the cylinder.