A one-piece low drag septum is provided for preventing escape of fluid from an introducer needle during removal of such a needle from a catheter and introducer needle assembly. The septum generally includes a distal portion, a proximal portion, a cavity portion, and a longitudinal axis. The distal portion acts as a primary seal to prevent escape of blood from the catheter into the assembly and is generally positioned furthest away from the user of the apparatus and nearest the patient. The cavity portion reduces friction placed on the introducer needle. The proximal portion of the septum acts as a secondary seal to prevent escape of material from the cavity, seals the cavity, and wipes the needle as it is being withdrawn from the catheter assembly.