Needle devices are disclosed in which a needle having a wall defining a needle lumen has a notch (120) formed through the wall. A transparent or semi-opaque window cover (130) made from a biocompatible material is provided over the notch. Blood flow through the needle lumen can be viewed through the notch with the window cover. The needle with the notch and window cover may be used with a variety of needle applications, including as catheter assemblies, indwelling assemblies, and most if not all over-the-needle type devices.