The ASC X12 Implementation Guides are copyrighted documents and must be purchased from this site. Companion Guides are generally created by health plans and clearinghouses for distribution to health care providers, other clearinghouses, and software vendors.
WEDI and ASC X12 have worked together, with other industry representatives, to develop a Principles document, and associated templates for Transaction Instructions (TI) and Trading Partner Information (TP). In concert, the Principles document, along with the templates encourage consistent format, structure, and content in companion guides developed by individual health plans and clearinghouses.
Companion Guides claiming compliance with the conventions must follow all the principles and instructions in the principles document and the templates.