An extravascular system for accessing the vasculature of a patient including a catheter having an interior surface, a needle disposed within the catheter, and/or a needle cap defining at least one capillary space and including a flexible seal surrounding the at least one capillary space. The flexible seal may engage the interior surface of the catheter. A method of controlling exposure to a liquid from an extravascular system including providing a wicking material positioned adjacent to a flow channel such that any fluid located external to the flow channel is retained by the wicking material. The wicking material may be incorporated into any extravascular system where exposure to liquids is undesirable.