An assembly and method for percutaneous placement of a catheter comprising an elongated hollow catheter having a distal end and a reduced cross-section portion at a proximal end thereof. An introducer needle is slidably mounted over said catheter. The introducer needle has an elongated slit adapted to slide over the reduced cross-section portion to separate the needle from the catheter. A syringe may be attached to the proximal end of the catheter. Also, a valve may be attached to the catheter to permit easy collection of fluid.