A catheter assembly provided with a door, comprising: a catheter adapter (20) with a proximal end (22), a distal end (24) and a tubular passage (26) extending between them, also comprising the adapter (20) catheter a side door (30) that forms a path (46) through a side wall of the catheter adapter (20) and in communication with the tubular passage (26)； a blood control septum (60) disposed in the tubular passage (26) and which divides the tubular passage (26) into a proximal chamber and a distal chamber； a septa actuator (90) with an outer diameter and disposed in the proximal chamber (70), and having a base (92), a tip (94) and a body (96) extending between them, the position being positioned tip (94) near the blood control septum (60) and the base (92) being positioned near the proximal end of the catheter adapter (20)； and a valve (40) disposed in the tubular passage (26) and forming a closure between the tubular passage (26) and the side door path (30)； characterized in that the catheter assembly also comprises an actuator retention tab (98) with an outer diameter and positioned on the outer surface of the body (96)； and the valve (40) is provided with a retaining ring (48) comprising an inner diameter greater than the outer diameter of the septum actuator (90) and smaller than the outer diameter of the retaining tongue (98) of the actuator, the actuator retention tab (98) being positioned on the outer surface of the body (96), between the blood control septum (60) and the actuator retention ring (48).Un conjunto de catéter provisto de una puerta, que comprende: un adaptador (20) de catéter con un extremo proximal (22), un extremo distal (24) y un paso tubular (26) que se extiende entre ellos, comprendiendo también el adaptador (20) de catéter una puerta lateral (30) que forma una vía (46) a través de una pared lateral del adaptador (20) de catéter y en comunicación con el paso tubular (26)； un septo (60) de control de sangre dispuesto en el paso tubular (26) y
