The C-CDA R2.1 Implementation Guide (IG) provides an overview of the Clinical Document Architecture (CDA) base standard and provides information on how to understand and use CDA templates CDA templates for representing common clinical document types are defined in the IG at the document, section, entry level, and other supporting templates.
HL7 Specifications
CDA
HL7 CDA® R2 IG: C-CDA Templates for Clinical Notes STU Companion Guide Release 3
The Office of the National Coordinator (ONC) releases periodic proposed rules, and final rules, which reference the use of Consolidated CDA (C-CDA). The Companion Guide to Consolidated Clinical Document Architecture (C-CDA) provides supplemental guidance.