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Information Blocking Key Terms and Acronyms

Key terms, definitions, and acronyms associated with the regulations.

Key Terms

  • Information Blocking: The body of works that are the information blocking provisions of the 21st Century Cures Act.
  • information blocking: The act of intentionally withholding patient information. 


  • AEU: Access, exchange, or use
  • EHI: Electronic health information 
  • Health IT: Health information technology
  • USCDI: United States Core Data for Interoperability standard; particularly, version 1.
  • FHIR(R): Fast Healthcare Interoperability Resources 
  • ONC: Office of the National Coordinator for Health IT 
  • CMS: Centers for Medicare & Medicaid Services
  • OIG: Office of Inspector General
  • ADT: Admission, discharge, and transfer notifications 
  • PI Program: Promoting Interoperability program
  • APIs: Application programming interfaces
  • PHI: Protected health information



Before October 6, 2022: Electronic protected health information (ePHI) as the term is defined for HIPAA to the extent that it would be included in a designated record set (other than psychotherapy notes or information compiled in reasonable anticipation of, or for use in, a civil, criminal, or administrative action or proceeding), regardless of whether the group of records are used or maintained by or for a covered entity.

Like ePHI, the data that constitutes EHI is not tied to a specific system in which the EHI is maintained. Health information that is de-identified consistent with the requirements of 45 CFR 164.514(b) is not included in the definition of EHI for the purposes of information blocking. Thus, any individually identifiable health information that is transmitted by or maintained in electronic media is EHI to the extent that the information would be included in the designated record set.

After October 6, 2022: EHI identified by the data elements represented in the USCDI standard.


Health information that identifies or reasonably could be used to identify an individual (individually identifiable health information) with certain exclusions such as Family Educational Rights and Privacy Act (FERPA) education or treatment records and employment records of a covered entity. Such health information not only identifies the individual, such as demographic information, but also relates to the past, present, or future physical or mental health or condition of an individual; the provision of health care to an individual; or payment for care. The information may be maintained or transmitted in any form or media (e.g., electronic, paper, or oral).


Any PHI that is maintained or transmitted in electronic form.

Designated record set

Medical records and billing records about individuals; enrollment, payment, claims adjudication, and case or medical management record systems maintained by or for a health plan; and/or other records that are used, in whole or in part, to make decisions about individuals.


Any item, collection, or grouping of information that includes PHI.