A catheter system may include a catheter adapter, a catheter extending distally from the catheter adapter, an introducer needle extending through the catheter, a flash chamber in fluid communication with a needle lumen of the introducer needle, and a seal element. The introducer needle may include a wall defining the needle lumen, a first notch formed through the wall, and a second notch formed through the wall. The seal element may be proximal to the first notch and the second notch and within the catheter between an outer surface of the introducer needle and an inner surface of the catheter. The seal element may prevent priming fluid from travelling distal to the seal element. The seal element in conjunction with the first notch, the second notch, and the flash chamber may facilitate pressure-driven blood flow into the catheter for detection of flashback and transfixing when priming occurs prior to insertion into vasculature.
