About DenialCodeGuide

DenialCodeGuide is a free reference tool for medical billing professionals. We help billing specialists, coders, and revenue cycle managers quickly look up CARC (Claim Adjustment Reason Codes) and RARC (Remittance Advice Remark Codes) to understand why claims were denied or adjusted, and what to do about it.

What We Provide

• Plain-language explanations of every active CARC and RARC code
• Group Code differentiation — CO, PR, OA, and PI pages explain who bears the cost
• Common causes with frequency indicators
• Step-by-step resolution guides specific to each code and group
• Prevention tips to reduce future denials
• RARC pairing tables showing which remark codes accompany each denial

Our Methodology

All content on this site is original and based on publicly available industry sources including MAC (Medicare Administrative Contractor) guides, payer documentation, and professional billing resources. We do not copy or reproduce X12 official code definitions.

Code data is updated to reflect changes published by X12 in their periodic code update cycles (typically three times per year).

Disclaimer

This site is for informational purposes only and does not constitute professional medical billing advice, legal advice, or compliance guidance. Denial code definitions and resolution guidance are based on publicly available industry sources and general billing practices.

Always verify information against your specific payer contracts, current coding guidelines, and applicable regulations. Consult a certified billing specialist, compliance officer, or legal professional for advice on specific claim issues.

We are not affiliated with X12, CMS, any Medicare Administrative Contractor, or any payer organization. CARC and RARC codes are maintained by X12 — visit x12.org for official definitions.

Contact

For questions or corrections, please reach out via our contact form.