Question: What’s the difference between simple/single incision and drainage (I&D) and complicated/multiple? North Carolina Subscriber Answer: CPT® has divided several I&D codes into pairs designated as either “simple or single” or “complicated or multiple”: While documentation should make it easy for you to determine if your pediatrician performed one or multiple procedures, from a coding perspective, the definition of simple and complicated is not so clear. The CPT® book does not provide definitions for the terms; instead, you should look to guidance found in CPT® Assistant if you are faced with a choice between codes. Per a Q&A that appeared in the December 2006 issue of CPT® Assistant [Volume 16: Issue 12], CPT® does not define ‘simple’ or ‘complex’ in this context. Instead, CPT® Assistant says, ‘the choice of code is at the physician’s discretion, based on the level of difficulty involved in the incision and drainage procedure.”