Proper use of 90782 billing code Like any other medical billing code, there is an appropriate time to use the current procedural terminology code 90782. Some people wonder if this code is appropriate when doing medical billing for a tetanus toxoid injection in the emergency room. In medical billing, the best CPT code is the code that most accurately describes the service. In the emergency room scenario, it would not be appropriate to do medical billing for a 90782 (Therapeutic, prophylactic, or diagnostic injection; subcutaneous or intramuscularly) for a tetanus shot. In the emergency room, it would be very difficult to prove it medically necessary for a physician to administer …