A prefilled syringe provides for secure assembly of the components prior to use. The syringe includes a hollow barrel having opposed open ends and a plunger manually operable within one of the ends of the barrel. An injection holder is attached to the other end of the barrel. An injection member such as a hypodermic needle assembly or an IV access device is removably secured to the injection holder. The cover accommodates the injection member and is removably attached to the injection holder. The cover is movable with respect to the injection holder from a first position where the cover is retained on the injection holder to a second position where the cover is removed from the injection holder. Movement of the cover from the first position to the second position assures the removable securement of the injection member to the injection holder.