You need to have modifier 25 on the E/M code and then you will have to have modifier 59 on the admin code for the injection. They are bundling this with the E/M code. So if you are seeing a pt for 99213 for some other reason and then in the midst of the visit the provider finds out they need a PPD. The claims will look like this:
99213 25 (whatever the DX is)
86580 V74.1
96372 59 V74.1
This should get the claim paid. I have been filing all of our vaccines/PPD/injections this way and I have not had a problem. I hope this helps for you.