You shouldn't be coding, the doctor should, especially since your not trained, you cannot learn simply by looking at the CPT Code book. The ultimate responsibility of coding falls on the doctor. If you are not qualified or trained, when he hands you the superbill you look it over and if it's not complete, give it back to him. Coding is done using the medical chart and is based on the elements of the E&M, ONLY he is in there with the patient and is responsible for documenting it, therefore responsible for assigning the proper codes and modifiers.