A catheter assembly (10) is disclosed having a catheter adapter (14) and aneedle hub (45). The catheter adapterhas an inner lumen (16) with a septum (50) located within the inner lumen. Anintroducer needle (20) is inserted through the innerlumen. A septum activator (80) also located within the inner lumen, such thata distal end of the septum activator contacts theseptum. The septum activator has an internal cavity (88) and a cavity seal(131) forming a surface of the internal cavity.
