A method of preventing blood leakage through a septum of a catheter assembly when a needle is disposed within a slit of the septum may include providing a lubricant within multiple gaps disposed between an outer surface of the needle and the slit. The lubricant may include a viscosity greater than 1,000 centipoise. Providing the lubricant within the multiple gaps may include applying the lubricant to the outer surface of the needle, and inserting the lubricated needle distally through the slit of the septum. Providing the lubricant within the multiple gaps may include applying the lubricant to a tip of a septum actuator of the catheter assembly, and penetrating the septum with the lubricated septum actuator. Providing the lubricant within the plurality of gaps may include dispensing the lubricant within the slit of the septum prior to insertion of the septum into the lumen of the catheter adapter.