Just keep in mind that there are a lot of people that are allergic to iodine that don't know it. Make sure if you're going to use it, test it out first. Also, if you're allergic to shellfish, you're probably allergic to iodine as well.
Another thing to keep in mind it that if you're sterilizing...
I'm a phlebotomist and I would be VERY careful doing this. Sebastian is right, you should probably have a trained professional do this for you, though if it's the actual blood letting that turns you on, then I can see where that can be difficult. Please do not use a needle if you're not trained...