CARC Code
31
Patient Not Identified as Insured
The insurance company cannot find the patient in their system as a covered member. This means the patient's information on the claim does not match any active policy holder or dependent in the payer's records.
eligibilityHow to resolve this denial
▶✓ Pre-action checklist — verify before contacting the payer
Review the full remittance advice (ERA/EOB) for additional RARC codes that explain the denial.
Verify the claim was submitted with correct patient eligibility and benefit information.
Check if this denial applies to a specific line item or the entire claim.
▶More about CO-31 — stats, related codes, appeal template
82%
Recovery Rate
5-14 days
Avg. Resolution
Medium
Difficulty
Occasional
Frequency
Payer-Specific Notes
How major payers handle CARC 31 by specialty.
Medicare
Medicare Beneficiary Identifier (MBI) replaced HICN; ensure MBI format is correct (11 characters, no special chars)
Medicaid
Medicaid IDs are state-issued; verify with state portal; some states use SSN-based IDs
Common 835 Combinations
CARC 31 most often appears with these Group Code + RARC combinations on 835 remittances.
Appeal Letter Template
Generic appeal template for CARC 31 denials.
We are resubmitting claim [CLAIM_NUMBER] with corrected patient identification information. Patient [PATIENT_NAME] (DOB: [DOB]) is enrolled under Member ID [CORRECTED_ID]. We have verified this information directly with the patient and confirmed enrollment via eligibility check dated [CHECK_DATE].
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