DENIAL CODE · CO-15

CO-15: Authorization Number Missing or Invalid

Official (X12/WPC): "The authorization number is missing, invalid, or does not apply to the billed services or provider."

Why payers issue CO-15

The auth number was left off or mistyped
The auth was issued for a different code, provider, or date range
The rendering provider on the claim isn't the one named on the auth
The auth number format didn't match the payer's records

Is it recoverable? Usually recoverable — tie the correct, valid auth number to the claim, or show the service falls within an existing authorization.

How to appeal a Prior Authorization denial →

Common questions

What does CO-15 mean?

CO-15 means an authorization exists in the picture but the number on the claim is missing, wrong, or doesn't match the service or provider billed. Different from CO-197, where no auth was obtained at all. The authorization number is missing, invalid, or does not apply to the billed services or provider.

How do I appeal or fix a CO-15 denial?

Usually recoverable — tie the correct, valid auth number to the claim, or show the service falls within an existing authorization. Common causes: the auth number was left off or mistyped; the auth was issued for a different code, provider, or date range; the rendering provider on the claim isn't the one named on the auth; the auth number format didn't match the payer's records.

Is a CO-15 denial worth appealing?

Usually recoverable — tie the correct, valid auth number to the claim, or show the service falls within an existing authorization. You only pay on what's actually recovered, so there's no cost to working the ones that are winnable.

Other denial codes

CO-197 · Precertification / Authorization Absent →CO-50 · Not Medically Necessary →CO-16 · Missing or Invalid Information →CO-45 · Charge Exceeds Fee Schedule →CO-97 · Bundled into Another Service →CO-29 · Timely Filing Expired →CO-96 · Non-Covered Charge →OA-18 · Duplicate Claim →OA-22 · Coordination of Benefits →CO-11 · Diagnosis Inconsistent with Procedure →CO-151 · Too Many Services (Frequency/MUE) →CO-B7 · Provider Not Eligible →CO-27 · Coverage Terminated →CO-204 · Not Covered Under Current Plan →CO-109 · Not Covered by This Payer →CO-119 · Benefit Maximum Reached →CO-4 · Modifier Inconsistent or Missing →OA-23 · Prior Payer Adjudication Impact →CO-24 · Charges Covered Under Capitation →CO-26 · Expenses Incurred Prior to Coverage →CO-54 · Assistant Surgeon Not Covered →CO-55 · Experimental / Investigational →CO-58 · Inappropriate Place of Service →CO-59 · Multiple/Concurrent Procedure Reduction →CO-107 · Related/Qualifying Claim Not Identified →CO-167 · Diagnosis Not Covered →CO-170 · Denied for This Provider Type →CO-181 · Procedure Code Invalid on Date of Service →CO-182 · Procedure Modifier Invalid on Date of Service →CO-183 · Referring Provider Not Eligible to Refer →CO-185 · Rendering Provider Not Eligible →CO-198 · Precertification / Authorization Exceeded →CO-226 · Requested Provider Information Not Provided →CO-231 · Mutually Exclusive Procedures →CO-234 · Procedure Not Paid Separately →CO-236 · Procedure/Modifier Combination Not Compatible →CO-242 · Out-of-Network / Non-Network Provider →CO-252 · Documentation Required to Adjudicate →CO-253 · Sequestration Reduction →CO-256 · Not Payable Per Managed-Care Contract →CO-288 · Referral Absent →CO-B15 · Qualifying Service Not Received →CO-B16 · New Patient Qualifications Not Met →CO-A1 · Claim/Service Denied (Remark Required) →

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