Insurance Claim Denial Codes Explained

Every denied claim on your EOB or remittance carries a reason code. Find your code below to see what it means, why insurers use it, and how to appeal it. Then draft your letter with the free appeal letter generator.

Common CO and PR denial codes

• CO-45 — Charge Exceeds Fee Schedule

  The insurer reduced payment because the charge exceeds the contracted or fee schedule amount.

• CO-50 — Non-Covered Services

  The payer determined the service is not medically necessary or is otherwise non covered under the benefit plan.

• CO-96 — Non-Covered Charge

  The procedure or supply is not covered under the patient's current benefits.

• CO-97 — Payment Included in Allowance

  The benefit for this service is included in the payment or allowance for another procedure that was already adjudicated.

• CO-151 — Frequency Limitation

  The payer reduced payment because the documentation does not support this many services or this frequency of services.

• CO-16 — Missing Information

  The claim or service lacks information or has submission or billing errors needed for adjudication.

• CO-167 — Diagnosis Not Covered

  The diagnosis or diagnoses on the claim are not covered under the patient's benefit plan.

• CO-18 — Duplicate Claim

  The payer considers this claim a duplicate of a previously processed claim.

• CO-22 — Coordination of Benefits

  Another payer may be responsible for this claim.

• CO-29 — Timely Filing Limit

  The claim was not filed within the payer's required timeframe.

• PR-204 — Service Not Covered Under Benefit Plan

  This service, equipment, or drug is not covered under the patient's current benefit plan and may be patient responsibility.

• CO-4 — Modifier Inconsistent

  The procedure code modifier is inconsistent with the billed service.

• CO-197 — Prior Authorization Required

  Prior authorization or precertification was not obtained.

• CO-204 — Service Not Covered Under Benefit Plan

  This service is excluded from the patient's benefit plan.

• CO-11 — Diagnosis Inconsistent with Procedure

  The diagnosis code on the claim is inconsistent with the procedure performed according to payer edits.

• CO-27 — Expenses After Coverage Terminated

  Expenses were incurred after the patient's coverage terminated.