Described are the changes to ICD-10-CM and PCS and potential challenges regarding their use in the US for financial and administrative transaction coding under HIPAA in 2013. Using author constructed derivative databases for ICD-10-CM and PCS it was found that ICD-10-CM's overall term content is seven times larger than ICD-9-CM: only 3.2 times larger in those chapters describing disease or symptoms, but 14.1 times larger in injury and cause sections. A new multi-axial approach ICD-10-PCS increased size 18-fold from its prior version. New ICD-10-CM and PCS reflect a corresponding improvement in specificity and content. The forthcoming required national switch to these new administrative codes, coupled with nearly simultaneous widespread introduction of clinical systems and terminologies, requires substantial changes in US administrative systems. Through coordination of terminologies, the systems using them, and healthcare objectives, we can maximize the improvement achieved and engender beneficial data reuse for multiple purposes, with minimal transformations.