tape

I bugged and bugged the hospital I work at to order start kits...as everthing you need comes in a little kit...so after I start the IV........I get the tape roll and tear what I need and secure it right off the sterile roll......it can be a little tricky with some catheters such as the introcan or insyte...so what I do is have an extension set with a valve on it and I attach that and flush and then my hands are free to use the tape....so the answer is tear as you need it...not before

Here's what I teach my students to do:

Once the IV start kit has been opened, the top of that package (the one with the writing on it regarding the kit itself) is layed with the wording down onto your table. Then, the tape is removed from the package and a piece is torn off of the roll. The ends are then double faced, as this has been "manhandled" by that nurse and it is placed on the pkg top, sticky side up. Then once your catheter is inserted, and the ext set with needle-less injection cap attached is leur-locked onto the IV catheter, the nurse simply touches the tape with his or her gloved hand and places that tape over the hub/ext set connection to secure. The double faced ends are then ripped off and it is then flushed and dressed.
Hope it helps..
DD