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Denials and Appeals/Intermediate/25 minutes/Reviewed 2026-07-10

How to Read an ERA: Group Codes, CARCs, and RARCs

Translate an 835 remittance into financial responsibility, root cause, and the next operational action.

Quick answer

The group code assigns the adjustment category, the CARC gives the general reason, and RARCs add detail. Read the full combination at claim and line level before deciding who owns the balance or what to do next.

Rules to know

  • CO generally signals contractual obligation and PR patient responsibility under the remittance rules.
  • A CARC may be too broad without its associated RARC.
  • PLB adjustments are provider-level, not automatically tied to one claim.
  • Never bill a beneficiary merely because a payer did not pay.

Operational workflow

  1. 01Reconcile payment and adjustment amounts at line and claim level.
  2. 02Read group code, CARC, every RARC, and payer message.
  3. 03Classify as rejection, denial, reduction, patient responsibility, or provider-level adjustment.
  4. 04Route to correction, payer inquiry, reopening, appeal, refund, or contractual posting.
  5. 05Track the final root cause instead of only the code number.

ERA interpretation sequence

A CARC number alone is not a complete denial answer. Interpret the adjustment at the claim or line level and preserve the complete code combination.

ElementQuestion it answersPosting control
Group codeWhich financial-responsibility category is assigned?CO and PR are not interchangeable. Do not infer patient liability from nonpayment alone.
CARCWhat general adjustment reason did the payer report?Use the current code meaning and the amount attached to that adjustment.
RARCWhat additional explanation or action detail applies?Read every associated remark; one CARC may lead to different actions depending on the RARC.
Claim or line statusWas the claim rejected, denied, reduced, pending, or paid?Choose correction, inquiry, reopening, appeal, or contractual posting based on adjudication status.
PLBIs this a provider-level balance adjustment?Do not force a PLB amount onto a patient account without a valid reconciliation method.

Common failure modes

  • Reading only the CARC.
  • Posting every PR amount without checking notices and contract rules.
  • Treating an adjustment as a denial requiring an appeal.

Knowledge check

Which code adds detail to a general claim adjustment reason?

Official sources

Health Care Payment and Remittance AdviceCenters for Medicare & Medicaid ServicesReviewed 2026-07-10Medicare Claims Processing Manual (Publication 100-04)Centers for Medicare & Medicaid ServicesReviewed 2026-07-10

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IntermediateCorrected Claim, Reopening, or Appeal?AdvancedOriginal Medicare Appeals: Five Levels and Deadlines

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