A method of improving the surface lubricity of extruded thermoplastic tubing for inclusion in medical devices wherein the tubing is intended for insertion into the human body includes providing a finite section of hollow extruded thermoplastic tubing which has been cooled to room temperature following an extrusion process. The tubing has a first lubricity level on its outer surface. The method steps further include maintaining the tubing substantially at room temperature conditions and applying a longitudinal stretching force to the tubing sufficient to exceed the elastic limit of the tubing whereby the tubing is deformed from its original dimensions. This stretching produces a second lubricity level on the outer surface of the tubing which is an improvement over the first lubricity level so that the tubing may slide more clearly and with less friction during insertion.This method of improving the surface characteristics of extruded thermoplastic tubing is adaptable to a method of fabricating an intravenous catheter assembly wherein a section of extruded thermoplastic tubing is connected to a hub which serves as a connection device for delivering solutions to a patient. The tubing may be stretched either before or after its insertion into the hub. As a result of this stretching, the surface lubricity of the tubing is improved to allow it to slide more freely during intravenous insertion.