For the period of time when EHI is “limited to the United States Core Data for Interoperability (USCDI),” does that mean the information blocking regulations apply only to EHI that is recorded or requested according to the applicable standards within the USCDI?

No. The definition of electronic health information in 45 CFR 171.102 is not limited by whether the data is recorded or could be exchanged using any particular technical functionality or standard. The information blocking definition (45 CFR 171.103) provides that before October 6, 2022, electronic health information (EHI) is limited to the subset of EHI represented by the data elements identified by the USCDI standard. This limitation of EHI for purposes of the information blocking definition is not contingent on whether those data elements are recorded or represented using the specific content and vocabulary standards in the USCDI standard at 45 CFR 171.213. On and after October 6, 2022, the information blocking regulations in 45 CFR part 171 pertain to all EHI as defined in 45 CFR 171.102.