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CARC 22 · CO-22

CARC 22 Denial: This care may be covered by another payer per coordination of benefits — How to Fix and Appeal

Reviewed by QuickIntell RCM Editorial Team · Last reviewed

Updated

TL;DR

CARC 22 (X12 This care may be covered by another payer per coordination of benefits). CARC 22 means the payer believes another insurer is primary for this patient and is not paying until you confirm.

Official X12 description

“This care may be covered by another payer per coordination of benefits.”

Source: X12 Claim Adjustment Reason Codes. The X12 External Code Lists are the single authoritative source for every CARC descriptor — always verify against the current release before building a claim-scrub rule.

What CARC 22 actually means

CARC 22 means the payer believes another insurer is primary for this patient and is not paying until you confirm. This is a coordination-of-benefits (COB) issue, not a medical-necessity or coding issue. Usually the patient has active secondary coverage the payer knows about, or a workers-comp / motor-vehicle / third-party-liability flag, and the payer wants the primary EOB on file before they'll adjudicate. The fix is to verify the correct primary, rebill the correct primary first, then rebill this payer as secondary with the primary EOB.

Common root causes

  • Patient has Medicare as secondary to an active employer group health plan, or vice versa.
  • Patient has two commercial plans and the birthday rule or other COB order of benefits was not followed.
  • Injury was related to a motor vehicle accident, workers-compensation claim, or other third-party liability.
  • Medicare Secondary Payer questionnaire data is missing or incorrect.

Prevention checklist

  • Ask COB questions at every check-in, not just at registration. Coverage changes mid-year.
  • Configure the PM system to prompt for an MSP questionnaire on every Medicare encounter.
  • Query CMS eligibility (HETS 270/271) for Medicare patients to confirm primacy before billing.
  • Use dual-coverage eligibility checks (via the clearinghouse) at scheduling when two insurances are on file.

Appeal strategy — step by step

Most CARC 22 denials clear faster with the right remediation than with a formal appeal. Work the steps in order and escalate only when a lower-effort path has been ruled out.

  1. 1If the payer is correct about another primary, rebill the primary first, then submit this payer as secondary with the primary's 835 or paper EOB.
  2. 2If the other coverage is terminated, submit proof of termination (termination letter, eligibility file from the prior payer) with a COB-update letter.
  3. 3For auto / workers-comp denials where health is actually primary, include the denial from the auto/WC carrier along with the corrected claim.
Sample appeal-letter language for CARC 22
[Provider letterhead] Re: Appeal of CARC 22 — Claim #{claim_number} Member: {member_name} · Member ID: {member_id} Date(s) of Service: {dos} On {remittance_date} this claim was adjusted with CARC 22: "This care may be covered by another payer per coordination of benefits." We respectfully request reconsideration. The X12 External Code List definition of CARC 22 does not apply to this claim for the following reasons: 1. [Cite the clinical / coding / policy fact that rebuts the adjustment] 2. [Cite the supporting documentation attached — op note, EOB, LCD/NCD citation, NCCI edit indicator, modifier rationale] 3. [Cite the payer's own policy where applicable] Attached: {list supporting documents} Please process payment under the member's benefits. If additional information is required, contact the billing office at {provider_phone} or {provider_email}. Sincerely, {billing_manager_name}, {credentials}

Edit the bracketed fields before sending. This template is a starting point; a payer-specific appeal form may still be required — check the provider portal first.

Payer-specific notes

Payer-specific behavior for CARC 22 publishes here as the QuickIntell anonymized denial ETL ingests sufficient volume. In the meantime, consult the payer directory for the relevant provider manual and appeal form.

How common is CARC 22?

Search demand rank
#5

Out of 306 seeded CARCs, ranked by combined US monthly search volume for "CARC 22", "CO-22 denial", and "denial code 22".

Platform frequency
Pending ETL

Platform frequency ranks publish once the anonymized denial-rate pipeline reaches the publication threshold (strategy §12 Phase 2).

How QuickRCM prevents CARC 22

QuickRCM catches the root causes above before the 837 leaves the clearinghouse:

  • Claim-scrub rules fire on every root cause listed above — the scrub references the same X12 CAS segment logic that drives the denial, so what the payer checks, QuickRCM checks first.
  • When a denial lands, QuickRCM routes it to the correct worker with the documentation bundle already attached (op note, LCD citation, modifier rationale, EOB, primary 835).
  • Appeal templates tuned to each CARC (including this one) pull the supporting facts from the claim and fill the bracketed fields automatically.
See QuickRCM →Book a demo

Frequently asked questions — CARC 22

What does CARC 22 mean?

CARC 22 is an X12 Claim Adjustment Reason Code. The official definition is: "This care may be covered by another payer per coordination of benefits." In plain English, the payer is telling you cARC 22 means the payer believes another insurer is primary for this patient and is not paying until you confirm. This is a coordination-of-benefits (COB) issue, not a medical-necessity or coding issue. Usually the patient has active secondary coverage the payer knows about, or a workers-comp / motor-vehicle / third-party-liability flag, and the payer wants the primary EOB on file before they'll adjudicate. The fix is to verify the correct primary, rebill the correct primary first, then rebill this payer as secondary with the primary EOB.

How do I resolve a CARC 22 (CO-22) denial?

Start with the most common root cause: Patient has Medicare as secondary to an active employer group health plan, or vice versa. First step: If the payer is correct about another primary, rebill the primary first, then submit this payer as secondary with the primary's 835 or paper EOB. See the full remediation and appeal checklist on this page before filing a formal appeal.

Is CARC 22 patient responsibility?

No — CARC 22 is typically carried under CO (Contractual Obligation) or OA (Other Adjustment), which means it is the provider's responsibility, not the patient's. Do not bill the patient unless the 835 CAS group code is PR.

What does CARC 22 look like on an EOB or 835 remittance?

On the 835 ERA, CARC 22 appears in Loop 2110 CAS segment as "CAS*CO*22*{amount}". On a paper EOB the same code prints in the Adjustment/Denial Reason column with the X12 description: "This care may be covered by another payer per coordination of benefits." — usually paired with one or more RARC remark codes in the same remittance line for additional context.

Which RARC is paired with CARC 22?

CARC 22 is commonly observed with RARC MA04, MA92, N4. The RARC narrows the reason — for example, pointing at a missing modifier, an LCD citation, or a specific policy. Fix the underlying CARC first; the RARC usually clears with the corrected claim.

Disclaimer

This page is operational reference for medical-billing professionals. It is not legal, clinical, or contractual advice. X12 code descriptors are maintained by the X12 External Code Lists; always verify against the current X12 release and the payer's own published policy before submitting or appealing a claim.