If you are billing for a WIC visit where immunizations were given, you bill the diagnosis code of Z02.9 with a CPT code of 99211 EP for the visit, and then the diagnosis code of Z23 for immunizations, the CPT code for the particular vaccine, using the SL modifier. They should pay this way. You can’t bill a separate administrative fee for the WIC visit and the immunization visit when they were done at the same time. I hope this helps, along with the other information the ladies provided. Good luck!