A multi-use blood control catheter assembly (10) comprising: a catheter adapter (20) having a proximal opening (22), a distal end (24) and a fluid passage (26) extending among those, housing the distal end (24) of the catheter adapter (20) an intravenous catheter (12), a portion of the fluid passage (26) having a first diameter； a septum (150) arranged so that the inside of the fluid passage portion (26) can slide between a compressed or flexed state and a decompressed or distended state, the septum (150) having a second diameter that is at least equal to the first diameter such that the septum (150) divides the fluid passage (26) into a proximal fluid chamber (29) and a distal fluid chamber (27), the septum (150) also having a slit (154) that provides a passage through the septum； and a septum actuator (140) having a base (142) located inside the distal fluid chamber (27) and having a probe (144) configured for insertion into the recess (154) of the septum ( 150), in which, during use of the catheter assembly (10), the probe (144) forces the slit (154) to an open position when the septum (150) slides from the decompressed or distended state to the compressed or flexed state in response to an external device (70) that is being inserted into the proximal opening (22) of the catheter adapter (20), having an external surface of the probe (144) of the septum actuator (140) a conical shape that causes the septum (150) to be progressively compressed between an outer surface of the probe (144) and an inner surface of the fluid passage portion (26) when the septum (150) slides into the compressed state or chartered and the septum actuator (140) is pushed through the slit (15 4), forcing the compression of the septum (150) to the septum (150) in a proximal direction thereby causing the septum (150) to return to the decompressed or distended state when the external device (70) is removed from the proximal opening ( 22), with an internal lumen of the probe (144) having a conic
