MD - great point about the sterility and safety of the metal tip pen. I believe that many, like you use the sterile plastic needle cap to make your "mark" when doing injections. I would counter by claiming that the pen mark is thrice cleaned w/ betadine, isopropyl spray, and a final alcohol swip. While I like the needle cap approach, its a bit out of my squence since I make the mark first and do the unveiling of the needle last. I guess you could use another sterile needle cap as we use and discard several of those during the whole process. Thanks for corrective input!