DENIAL CODE · CO-151

CO-151: Too Many Services (Frequency/MUE)

CO-151 means the payer denied units above a frequency limit or Medically Unlikely Edit (MUE), paying some units and denying the rest.

Official (X12/WPC): "Payer deems the information submitted does not support this many/frequency of services."

Why payers issue CO-151

  • Units billed exceed the MUE or frequency cap for the code
  • A modifier for medically-necessary excess units was missing
  • The same code across lines/dates looked like over-billing
  • The cap applies but a documented exception was available

Is it recoverable? The denied units are recoverable when the chart supports them and the right modifier or MUE override applies.

How to appeal a Frequency / Units Exceeded (MUE) denial →Recover a Multiple Procedure Payment Reduction (MPPR) underpayment →

Common questions

What does CO-151 mean?

CO-151 means the payer denied units above a frequency limit or Medically Unlikely Edit (MUE), paying some units and denying the rest. Payer deems the information submitted does not support this many/frequency of services.

How do I appeal or fix a CO-151 denial?

The denied units are recoverable when the chart supports them and the right modifier or MUE override applies. Common causes: units billed exceed the MUE or frequency cap for the code; a modifier for medically-necessary excess units was missing; the same code across lines/dates looked like over-billing; the cap applies but a documented exception was available.

Is a CO-151 denial worth appealing?

The denied units are recoverable when the chart supports them and the right modifier or MUE override applies. 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-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 →CO-15 · Authorization Number Missing or Invalid →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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