External Code Lists

The table below includes external code lists maintained by X12 and external code lists maintained by others and distributed by WPC on behalf of the maintainer. Click on the name of any external code list to access more information about the code list, view the codes, or submit a maintenance request. These external code lists were previously published on either www.wpc-edi.com/reference or www.x12.org/codes. If you have questions about the X12-maintained lists, submit them on the X12 Feedback form.

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Name ID Scope Statement Maintained by Last Modified
Claim Adjustment Group Codes 974 These codes categorize a payment adjustment. CMG01 05/20/2018
Claim Adjustment Reason Codes 139 These codes describe why a claim or service line was paid differently than it was billed.  CMG03 03/01/2025
Claim Status Category Codes 507 These codes organize the Claim Status Codes (ECL 508) into logical groupings. CMG03 03/03/2020
Claim Status Codes 508 These codes convey the status of an entire claim or a specific service line. CMG03 03/01/2025
Error Reason Codes 977 These codes describe a processing error related to a particular EDI transmission. CMG02 07/01/2021
Industry Specific Remark Codes 973 These codes convey information about remittance processing or further explain an adjustment already described by a Claim Adjustment Reason Code (CARC) from ECL 139. CMG01 06/01/2020
Insurance Business Process Application Error Codes 895 These codes report application warnings and errors for insurance business processes. CMG02 07/12/2024
Insurance Descriptor Codes 979 These codes describe, identify, or clarify the insurance being reported in an eligibility and benefits response. CMG01 11/01/2024
Payment Type Codes These codes identify the type and purpose for a payment amount. CMS 03/01/2021
Property & Casualty Code Lists These codes are used by Property & Casualty organizations 01/31/2022
Provider Adjustment Reason Codes 967 These codes report payment adjustments that are not related to a specific claim, bill, or service. CMG01 11/01/2024
Provider Taxonomy Codes 682 These codes define the health care service provider type, classification, and area of specialization. NUCC 01/01/2024
Remittance Advice Remark Codes 411 These codes provide additional explanation for an adjustment already described by a Claim Adjustment Reason Code (CARC) or convey information about remittance processing. CMS 03/01/2025
Report Type Codes These codes provide exchange-related report type codes. They define the type of report being described. CMS 04/26/2024
Service Review Decision Reason Codes 886 These codes communicate the reason for the health care services review outcome. CMG01 08/01/2022
Service Type Codes 958 These codes identify business groupings for health care services or benefits. CMG01 01/01/2024
Service Type Descriptor Codes 981 These codes further clarify a benefit response which cites a Service Type Code (ECL 958). CMG01 04/01/2020