DISPOSITIF POUR PRELEVEMENTS SANGUINS MUNI D'UN SYSTEME D'ETANCHEITE

摘要

A blood extraction device includes a sample extraction tube having an open rear end and a first sealing surface at the rear end. A piston assembly includes a piston removably housed within the tube for movement between a retracted position toward the rear end and an extended position. The piston assembly also includes a piston rod portion extending through the open rear end of the tube. The piston rod portion has a reduced diameter portion along a substantial part of its length and an enlarged portion which defines a second sealing surface for complementary mating engagement with the first sealing surface when the piston is at its extended position. The piston is locked in its fully retracted position by the engagement of a forwardly facing annular flange on the piston assembly and a rearwardly facing annular step of the tube. Preferably the piston assembly includes a frangible joint to permit at least a part of the piston rod portion to be separated from the piston after the piston is in the retracted position.