Is a list of acceptable abbreviations required?    

Any examples are for illustrative purposes only
No, IM.02.02.01 EP 2 requires that organizations use 'standardized' abbreviations but does not require organizations to maintain a list of acceptable abbreviations.  Any reasonable approach to standardizing abbreviations, acronyms, and symbols is acceptable.  

Examples of different approaches may include: 
-Standardized abbreviations developed by the individual organization. 
-Use of a published reference source. However, if multiple abbreviations, symbols or acronyms are used for the same term, the organization identifies what will be used to eliminate any ambiguity.  
-If a standardized abbreviation list is created, staff should have knowledge and access to the list.