My cat has an Avid chip and bought a universal scanner, but I was told that there usually isn't a problem with non-ISO chips from the US. If you've already started the PETS process, you can buy a scanner (I think I picked mine up for like $150 online). If you do use an ISO chip, you have to make sure your vet has a reader that can read it.
I don't regret buying the scanner, though. I have it now for vet visits and border crossings here, and I know I will never have a problem with readers no matter if it's in the States or here.