Healthcare Claim Denial Codes Explained: CARC/RARC, CO/PR/OA/PI + Real Fix Steps

Use this guide to decode the denial family quickly, confirm what the payer is actually asking for, and apply safe fix steps before you appeal or rebill.

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TL;DR

✓ Start with the adjustment group: CO (contractual), PR (patient responsibility), OA/PI (other/payer initiated).
✓ Treat CARC as the “what happened” reason and RARC as the “what to submit next” hint.
✓ Fix claim data and prerequisites (eligibility, auth, NPI/taxonomy, dates, modifiers) before escalating.
✓ Avoid blind resubmits that create duplicate denials and burn timely filing windows.

Quick Navigation

Symptoms Root Causes Step-by-step fixes What NOT to do If it persists Code directory Related guides & hubs FAQ References

Symptoms / When you see this

✓ A claim returns with CO/PR/OA/PI and a short reason code.
✓ The remittance advice includes CARC and sometimes RARC.
✓ Your billing system shows “denied/rejected/not covered/needs info” without detail.

Root causes (grouped)

Most denials fall into a few buckets that you can validate quickly:

✓ Eligibility & coverage (plan not active for date of service, COB mismatch).
✓ Authorization & referrals (missing/invalid auth, mismatch on dates/CPT/units).
✓ Claim data quality (member ID, DOB, NPI/taxonomy, service location).
✓ Coding rules (invalid/obsolete code, modifier requirements, diagnosis mismatch).
✓ Contract/policy (out-of-network, non-covered benefit, bundling/edit rules).
✓ Timely filing & duplicates (wrong correction workflow, frequency indicators).

Step-by-step fixes (safe, prioritized)

✓ Classify the denial by group code (CO/PR/OA/PI) and by whether it is “data missing” vs “policy decision”.
✓ Read the remittance line detail first; CARC is the category, RARC often hints what to attach or correct.
✓ Validate eligibility and benefits for the date of service, including COB when applicable.
✓ Validate provider identity fields and enrollment (billing/rendering NPI, taxonomy, location).
✓ Validate authorization requirements and match all auth parameters to the claim.
✓ Validate coding: modifiers, units, and diagnosis support for the billed service.
✓ Only resubmit after confirming the payer’s correction workflow (corrected claim vs appeal).

What NOT to do

✓ Do not treat denial codes as a single diagnosis; confirm the scenario and remittance details.
✓ Do not rebill as new when the payer expects a corrected claim indicator.
✓ Do not “change codes to make it pay” without documentation support.

If it persists (escalation checklist)

✓ Collect: remittance line detail, CARC/RARC, claim image, and eligibility snapshot for date of service.
✓ Document what changed since initial submission (fields corrected, attachments added).
✓ If policy-driven, submit the minimum required documentation with a concise rationale.

Code directory within this guide

✓ Payers and contracts vary. The linked pages describe common interpretations and safe next steps.
✓ When a code is ambiguous, the remittance line detail is usually more specific than the code alone.

Code	Meaning	Next step
CO-109	Claim not covered by this payer — This code indicates that the payer is not responsible for covering the submitted claim.	Follow the checklist on the code page
CO-11	Diagnosis inconsistent with procedure — This code indicates that the diagnosis reported does not support the billed procedure according to payer rules.	Follow the checklist on the code page
CO-119	Benefit maximum reached — This code indicates that the patient has reached the maximum benefit limit for the service.	Follow the checklist on the code page
CO-125	Submission/billing error — This code indicates that an error occurred during claim submission or billing.	Follow the checklist on the code page
CO-128	Invalid billing modifier — This code indicates that the modifier submitted is invalid or not allowed for the billed service.	Follow the checklist on the code page
CO-133	Incorrect provider type — This code indicates that the provider type submitted does not match payer requirements for the service.	Follow the checklist on the code page
CO-141	Claim adjusted by payer — This code indicates that the payer adjusted the claim according to internal rules or policies.	Follow the checklist on the code page
CO-131	Claim-specific negotiated discount — This code indicates that a negotiated discount was applied to the claim.	Follow the checklist on the code page
CO-151	Payment adjusted due to contractual agreement — This code indicates that the payment amount was adjusted according to the provider’s contract with the payer.	Follow the checklist on the code page
CO-16	Claim lacks required information — This code indicates that the claim is missing required information needed for processing.	Verify the correct path/resource and prerequisites
CO-167	No authorization on file — This code indicates that no valid authorization was found for a service that requires prior approval.	Follow the checklist on the code page
CO-170	Payment adjusted due to referral absence — This code indicates that payment was adjusted because a required referral was not present.	Follow the checklist on the code page
CO-178	Claim did not contain sufficient information — This code indicates that the claim lacked sufficient information to support adjudication.	Follow the checklist on the code page
CO-18	Duplicate claim/service — This code indicates that the claim or service has already been submitted and processed.	Follow the checklist on the code page
CO-197	Precertification required — This code indicates that required precertification or authorization was not obtained before the service was provided.	Follow the checklist on the code page
CO-200	Non-covered service — This code indicates that the billed service is not covered under the payer’s policy.	Follow the checklist on the code page
CO-198	Preauthorization missing — This code indicates that required preauthorization was not obtained before services were provided.	Verify the correct path/resource and prerequisites
CO-204	Service not covered under plan — This code indicates that the service is excluded from coverage under the patient’s insurance plan.	Follow the checklist on the code page
CO-21	Missing/invalid place of service — This code indicates that the place of service information was missing or invalid on the claim.	Verify the correct path/resource and prerequisites
CO-22	Care may be covered by another payer — This code indicates that another payer may be responsible for covering the service.	Follow the checklist on the code page
CO-23	Impact of prior payer adjudication — This code indicates that claim processing was affected by a prior payer’s adjudication.	Follow the checklist on the code page
CO-24	Charges not covered — This code indicates that the charges are not covered under the terms of the patient’s insurance plan.	Follow the checklist on the code page
CO-26	Expenses incurred before coverage — This code indicates that the service was provided before insurance coverage became effective.	Follow the checklist on the code page
CO-27	Coverage terminated — This code indicates that the patient’s insurance coverage was not active on the date of service.	Follow the checklist on the code page

Tip: If your exact code isn’t listed, use the closest hub link above and browse related prefixes or message patterns.

FAQ

Is CO always contractual and PR always patient responsibility?

Commonly yes, but payers can apply variations. Treat CO/PR/OA/PI as strong hints, then confirm with the remittance line detail and payer rules.

What is the difference between CARC and RARC?

CARC describes why the payer adjusted or denied. RARC adds context and often indicates what documentation or data is required next.

Should I resubmit or appeal?

Resubmit when it is a correctable data/documentation issue and the payer supports corrected claims. Appeal when you dispute a coverage/policy determination. When unsure, confirm the payer workflow first.

Can the same denial code have different fixes?

Yes. The safest approach is to identify the bucket (eligibility, auth, claim data, coding edits, policy) and validate the most likely inputs in that order.

How do duplicate denials happen?

Often from resubmitting as a new claim when a corrected claim indicator is required, or from multiple parties billing similar services. Confirm correction rules before resubmitting.

Does “not covered” always mean excluded?

Not always. It can also indicate missing authorization, mismatch in plan eligibility for the date, or coding/benefit rules not met. Validate the basics before concluding exclusion.

What documentation helps most when escalating?

Eligibility/benefit responses, authorization confirmations, claim image, and the remittance line details with CARC/RARC. For policy denials, include the minimum clinical documentation the payer requires.

How should I use this site for healthcare codes safely?

Use code pages to understand common interpretations and checklists, then confirm your payer’s policy and workflow. When this guide says “commonly,” it’s signaling payer variation.

References / Notes

✓ Payer remittance advice and portal guidance
✓ X12 / HIPAA code sets (CARC/RARC)
✓ Provider manuals and claims submission rules