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Operating Rules FAQs

Guidance for the operating rules for frequently asked questions.


Issued by: Centers for Medicare & Medicaid Services (CMS)

Issue Date: August 02, 2020

Q: Can a health plan require a provider to use the health plan’s own proprietary Claims Adjustment Reason Code (CARC) and Remittance Advice Remark Code (RARC) combinations?

A: No. All covered entities must comply with the adopted payment and remittance advice operating rule requirements, which include specific CARC and RARC combinations to be used in electronic funds transfer (EFT) or electronic remittance advice (ERA) transactions. Payers are allowed to use (proprietary) combinations of CARCs and RARCs that are not in the CORE Operating rule as long as those combinations do not conflict with or fall within the 4 business scenarios and the combinations allowable under those scenarios.

Suggested changes and/or additional combinations for regular CARCs and RARCs outside of the CORE Rules may be submitted using the Washington Publishing Company's (WPC) change request form. These CARC and RARC lists are updated 3 times a year at WPC.

Requests for new CARC/RARC combinations allowable under the CORE Rules should be submitted to CAQH -CORE via the yearly Market-Based Adjustment process. These change requests should not be submitted to WPC.

Q: What is the applicability of the CAQH CORE “safe harbor"?

 A: The CAQH CORE Connectivity Rule Version C1.1.0 provides business rules and guidelines for a “Safe Harbor” for connectivity that application vendors, providers, and health plans (or other information sources) can be assured would be supported by any HIPAA covered trading partner. The “Safe Harbor” connectivity is HTTP/S. The CAQH CORE Connectivity Rule Version C 2.2.0 extends the “Safe Harbor” reference by further specifying the connectivity message envelope standards. While it is expected that all health plans and health care clearinghouses would be able to implement the Safe Harbor connectivity if requested by trading partners, the rule is not intended to require trading partners to remove existing connections that do not match the rule, nor is it intended to require that all covered entities use this method for all new connections.

Q: Can providers require both paper and electronic remittance advice (ERA) from a health plan?

A: Yes, according to the CAQH CORE electronic fund transfer (EFT) & electronic remittance advice (ERA) Operating Rule Set, providers can request both paper and ERA from a health plan during the provider’s initial implementation testing Per the CAQH CORE operating rules, specifically the CORE Payment & Remittance (835) Infrastructure Rule, a health plan is required to offer dual delivery for up to three payment cycles or 31 days, whichever is longer. Upon mutual agreement between the provider and the health plan, the timeframe for delivery of the proprietary paper claim remittance advices may be extended by an agreed-to timeframe.

Q: If a health plan cannot be certain whether an individual will be covered for a particular claim or what the patient financials will be – because, for instance, the health plan is a secondary payer and waits for adjudication by the primary payer before this information is known– is the health plan required to comply with the CORE Rule 260 Eligibility and Benefits Data Content (270/271) Rule?

A: Health plans must comply with the adopted operating rules and standards for the eligibility for a health plan transaction, including the CORE Rule 260 Eligibility and Benefits Data Content (270/271) Rule. The operating rules assume there is uncertainty with regard to individual coverage for a particular claim and patient financials because they recognize that a response to an eligibility inquiry is not final. An eligibility response from a health plan does not guarantee that the health plan will reimburse the provider for health services when a claim is submitted.

Q: Do the CAQH CORE Operating Rules for the Eligibility for a Health Plan and Health Care Claim Status transactions apply to direct data entry (DDE) transactions?

A: No, the operating rules would not apply to DDE transactions. For more information on operating rules, please go to

Q: Is CAQH CORE certification required for covered entities to be compliant with the CORE operating rules for eligibility and claims status?

A: No. CMS does not require compliance with any aspect of CORE certification. CORE currently administers a voluntary certification process for a fee.

Q: Who is required to comply with the adopted operating rules for claims status and eligibility?

 A: All HIPAA-covered entities are required to comply with the operating rules for claims status and eligibility. Covered entities include all health plans, health care clearinghouses, and health care providers who transmit health information in electronic form in connection with a transaction for which the Secretary has adopted a standard.

Q: If a health plan's product is not designed to require co-pays, deductibles, and/or co-insurance, is the health plan required to comply with the CAQH CORE Rule 260 Eligibility and Benefits Data Content (270/271) Rule; i.e. the requirement to return base financial responsibility related to the deductible, co-pay, and co-insurance in response to an electronic eligibility query?

A: Health plans must comply with the adopted operating rules and standards for the eligibility for a health plan transaction, including the CAQH CORE Rule 260 Eligibility and Benefits Data Content (270/271) Rule. If a health plan’s product is not designed to require co-pays, deductibles, and/or coinsurance, the operating rules allow a health plan to report patient financials as “0."

Q: What is the relationship between an operating rule and a standard?

A: Operating rules support the adopted standards for health care transactions by fostering and enhancing uniform use of the standards across the health care industry. Operating rules are defined as “the necessary business rules and guidelines for the electronic exchange of information that are not defined by a standard or its implementation specifications [adopted under HIPAA].” The statutory definition was codified at section 45 CFR 162.103 in the interim final rule (considered final).

Operating rules are business rules and guidelines that do not duplicate what is in the standard. Nor are operating rules inconsistent or in conflict with the standard. Operating rules typically go above and beyond the standard in terms of data content and other requirements.

Q: Where can I get answers to technical questions and help with implementing the ASC X12 5010 TR3 Reports, NCPDP D.0 and 3.0 and the CORE Operating Rules?

A: For questions about the ASC X12 transactions and standards, the ASC X12 provides support through its work group and committee members. The names of those subject matter experts can be found on the X12 website at the official ASC X12 website. The site also offers clarifications for certain common issues.

For questions about the pharmacy transactions and standards, subject matter experts may be reached through the National Council for Prescription Drug Programs (NCPDP).

For questions about the operating rules, staff members at the Committee on Operating Rules for Information Exchange (CORE) can be contacted.


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DISCLAIMER: The contents of this database lack the force and effect of law, except as authorized by law (including Medicare Advantage Rate Announcements and Advance Notices) or as specifically incorporated into a contract. The Department may not cite, use, or rely on any guidance that is not posted on the guidance repository, except to establish historical facts.