A method may include priming a catheter system. The catheter system may include a catheter adapter, a catheter, and an extension tube. The catheter system may also include a Y-adapter, which may include first and second arms. A distal end of the Y-adapter may be coupled to the extension tube. The catheter system may further include a vent cap, which may be coupled to the second arm. Priming the catheter system may include attaching an IV line to the first arm and delivering saline through the IV line to the catheter system such that the saline exits a distal tip of the catheter and clamping the IV line via a roller clamp on the IV line. The method may also include actuating the vent cap after priming the catheter system. The method may further include inserting the catheter into a vein of a patient after actuating the vent cap.