CARC 15: Missing, Invalid, or Non-Applicable Authorization Number

What it means

The payer denied the claim because the prior authorization number submitted either wasn't included, doesn't match their records, has expired, or was issued for different services or a different provider than what was billed.

Common causes

Authorization number was left off the claim entirely
Wrong authorization number was entered (typo or wrong patient/date)
Authorization was obtained for a different CPT/HCPCS code or service than what was actually billed
Authorization was issued to a different rendering provider, facility, or NPI than the one submitting the claim
Authorization had expired before the date of service
Authorization was for a different date range or number of visits/units than billed
Services were billed under the wrong payer (e.g., secondary payer authorization used on primary claim)

How to fix it

Pull the original authorization approval letter or portal record to confirm the exact authorization number, approved codes, date range, and authorized provider
Compare the authorized details against what was billed - check CPT/HCPCS codes, units, dates of service, and provider/NPI
If the authorization is valid but was omitted or mistyped, correct and resubmit the claim (or submit a corrected claim per payer rules)
If the authorization doesn't match the services billed, contact the payer's utilization management or prior auth department to clarify whether a retro-authorization or amendment is possible
If no authorization exists, determine whether the service required one and pursue a retroactive authorization request if the payer allows it
Document all communication with the payer, including reference numbers, for use in a resubmission or appeal

Appeal / resubmit

When appealing, include a copy of the original authorization approval and clearly map the authorized codes/dates/provider to the billed claim line by line. If the mismatch was a clerical error on your end, a corrected claim is usually faster than an appeal. If you believe the payer's system has an error (e.g., correct authorization on file but not matched), request written confirmation of the authorization details and reference that in your appeal. Note the appeal or reconsideration deadline stated in the remittance advice or payer policy, as this varies by payer.

Related codes

Frequently asked

Does this mean the service wasn't medically necessary?

No. This code specifically points to an authorization number problem, not a medical necessity denial. Medical necessity denials typically use different codes.

Can I just add the authorization number and refile?

If the authorization is valid and simply missing from the original claim, submitting a corrected claim with the correct authorization number is often the fastest fix, but confirm the payer's preferred process (corrected claim vs. appeal).

What if the authorization was for a different provider in our group?

Many payers require authorizations to match the specific rendering provider or NPI. You may need to request an amended authorization or a retro-authorization for the correct provider before resubmitting.

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This content is informational only and is not billing or legal advice. Always verify current requirements with the specific payer and applicable regulations.