ONC defines USCDI as “a standardized set of health data classes and constituent data elements for nationwide, interoperable health information exchange.” A data class is “an aggregation of various data elements by a common theme or use case” and a data element is “the most granular level at which a piece of data is represented in the USCDI for exchange.” USCDI v1 contains 16 data classes, e.g., patient demographics and procedures. Each data element is associated with a specific version of one or more standard vocabulary. Version 1 is the base requirement and the ONC 21st Cures Act final rule allows health IT developers to adopt and implement newer versions of the USCDI.
ONC has a data element and class submission system for people to suggest/submit ideas for new data elements and/or data classes. After a public comment period, ONC published version 2 in July 2021 and published version 3 with errata in October 2022. Version 3 has 19 data classes.
USCDI v1 patient demographics includes race, ethnicity, birth sex, and preferred language all with applicable terminology standards. The health IT certification criteria published in 2015 requires certified health IT to be capable of recording standardized data on a patient’s sexual orientation and gender identity, but USCDI v1 does not include these data elements and there are no terminology standards associated with the requirement. USCDI v2 added sexual orientation and gender identity to the patient demographics data class and changed birth sex to sex assigned at birth. Also, with a focus on health equity, v2 added the SDOH data class, courtesy of The Gravity Project, and four SDOH data elements to enable identification of specific needs in domains such as food, housing, and transportation insecurity, and to coordinate care and assistance to improve health outcomes.