How do I resolve a CO-B20 denial?

If wrong date of service was billed, suppliers may do a self service reopening in the Noridian Medicare Portal. When provided within 2 days prior to anticipated discharge to home, the discharge date must be billed If beneficiary was not inpatient on date items were provided, contact the facility to update their billing. You can find the NPI of the facility through the claim status page under expanded denial details of the NMP for that specific claim. Once that billing update is verified through Self Service, supplier can either do a self service reopening or rebill the claim for the correct date of service. See full Medicare contractor resolution steps at tryarceum.com.

Can I appeal a CO-B20 denial?

Yes. Most CO-B20 denials can be appealed within 60-180 days depending on payer. This is appealable if your practice actually provided the service and can document that the other provider did not furnish the care in question. Use our free tool to generate an appeal letter.

CARC Code

B20

🟡 Soft Denial

Service Furnished by Another Provider

The insurance company is denying or reducing payment because another provider already billed for all or part of this same service. This prevents duplicate payment for the same care.

contractual

Resolution: 85%Easy difficulty3-7 days avg

How to resolve this denial

Which payer denied this claim?

▶✓ 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-B20 — stats, related codes, appeal template

85%

Recovery Rate

3-7 days

Avg. Resolution

Easy

Difficulty

Rare

Frequency

Payer-Specific Notes

How major payers handle CARC B20 by specialty.

General

Confirm payer-specific policy for CARC B20 and submit corrected claim or appeal as appropriate.

Common 835 Combinations

CARC B20 most often appears with these Group Code + RARC combinations on 835 remittances.

COCO-B20+M115+N211Beneficiary resides in a Competitive bid area and items are being furnished by

Look up any combination →

Appeal Letter Template

Generic appeal template for CARC B20 denials.

Dear [Payer Name] Appeals Department, We are writing to appeal the denial of claim [CLAIM #] for patient [PATIENT NAME] (Member ID: [ID]) for services rendered on [DATE OF SERVICE]. The claim was denied with CARC B20: "Procedure/service was partially or fully furnished by another provider." We believe this denial is in error for the following reasons: [INSERT CLINICAL/ADMINISTRATIVE JUSTIFICATION] We respectfully request reconsideration and payment of this claim. Sincerely, [Provider Name / Billing Contact]

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