medical needle apparatus for transferring fluid includes syringe assemblies for fluid injection and phlebotomy systems for collecting blood samples . a case with an elongated cavity therein has an open end and a relatively closed end from which a hollow needle projects . an operating member fits through the open end of the case into the cavity and controls both fluid transfer and self - destruction of the apparatus after fluid transfer to prevent reuse . plastic deformable means responsive to pressure on the operating member in a direction toward the needle renders the apparatus non - reusable after fluid transfer either by actuating needle retraction or by increasing the lateral dimension of the operating member to prevent withdrawal . the apparatus is operable with a single hand to transfer fluid and actuate deformable means without re - positioning the hand on the apparatus .