Office injections

What is the proper way to bill for office injections when the patient brings in their own medication. We are receiving conflicting info.
Tx

this is what we do

we bill cpt 96372 and the hcpc code for the medication with a zero charge.have had no problem getting paid for the admin since that is the only cost to us. if the patient does see a provider then you would also bill the e/m service

re: Office injections

can you bill office level 99211 for nurse visit