Question: A patient reports to the ED complaining of dehydration, weakness, and flu-like symptoms. The ED physician performs an E/M service, during which he provides rehydration service.,. Final diagnosis is dehydration. How many CPT codes should I report for this service? Illinois Subscriber Answer: You'll only be able to submit a single code for this service. Though you may see codes for hydration, you can only bill these services in the facility, not the ED physician. Roll with it: When choosing the ED E/M code (99281-99285, Emergency department visit for the evaluation and management of a patient, which requires these 3 key components: ...) to represent the service, consider the work the physician performs during rehydration and vaccination when choosing a level. No matter what code you settle on, be sure to submit the following codes to represent the encounter: