Medical Claim Denial Codes

A complete reference guide to the most common insurance claim denial codes. Each entry explains what the code means, why it's triggered, how to appeal it, and how to prevent it from happening again.

84

Denial Codes Covered

54%

Of Denials Overturned on Appeal

<1%

Of Denials Are Appealed

60s

RediClaim Appeal Generation

Contractual Obligation (CO)

Adjustments that are the provider's responsibility due to contractual agreements with the payer.

CO-4 Very Common

Procedure Code Inconsistent with Modifier

The procedure code is inconsistent with the modifier used, or a required modifier is missing.

CO-11 Very Common

Diagnosis Inconsistent with Procedure

The diagnosis is inconsistent with the procedure. This means the ICD-10 code submitted does not support the medical necessity of the CPT procedure billed.

CO-15 Very Common

Missing or Invalid Authorization

The submitted authorization number is missing, incomplete, or invalid. The service required prior authorization that was not obtained or was not properly documented on the claim.

CO-16

Missing or Incorrect Information

Claim/service lacks information or has submission/billing error(s) needed for adjudication. This is one of the broadest and most common denial codes, covering a wide range of missing or incorrect data.

CO-18 Very Common

Duplicate Claim or Service

Exact duplicate claim/service. The payer has identified this claim as a duplicate of a previously submitted and processed claim.

CO-22 Common

Coordination of Benefits

This care may be covered by another payer per coordination of benefits. The payer believes another insurance should be primary.

CO-24 Common

Capitation Agreement Applies

Charges are covered under a capitation agreement or managed care plan. The service is included in the capitated payment the provider already receives.

CO-26 Common

Expenses Incurred Prior to Coverage

Expenses incurred prior to coverage. The date of service is before the patient's coverage effective date with this payer.

CO-27 Common

Expenses After Coverage Terminated

Expenses incurred after coverage terminated. The date of service is after the patient's coverage end date with this payer.

CO-29 Common

Timely Filing Limit Exceeded

The time limit for filing has expired. The claim was not submitted within the payer's timely filing deadline.

CO-31 Common

Patient Not Identified as Insured

Patient cannot be identified as our insured. The payer cannot locate the patient in their system based on the submitted information.

CO-35 Less Common

Lifetime Benefit Maximum Reached

Lifetime benefit maximum has been reached. The patient has exhausted their lifetime benefit allowance for this service or benefit category.

CO-39 Common

Authorization Request Denied

Services denied at the time authorization/pre-certification was requested. The payer denied the prior authorization request for this service.

CO-40 Common

Not Qualified as Emergent/Urgent

Charges do not meet qualifications for emergent/urgent care. The payer has determined that the services do not qualify as emergency or urgent care.

CO-45

Charges Exceed Fee Schedule

Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement. The billed amount is higher than what the payer allows for this service.

CO-50

Not Medically Necessary

These are non-covered services because they are not deemed medically necessary. The payer has determined that the submitted clinical information does not establish medical necessity for the billed service.

CO-55 Common

Experimental or Investigational

Procedure, treatment, or drug is deemed experimental or investigational by the payer. The service is not covered because the payer considers it unproven or not yet accepted as standard practice.

CO-96 Common

Non-Covered Charges

Non-covered charge(s). At least one remark code must be provided to explain why the charge is not covered.

CO-97 Very Common

Service Included in Another (Bundling)

The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated. This is a bundling denial.

CO-109 Common

Claim Not Covered by This Payer

Claim/service not covered by this payer/contractor. You must send the claim/service to the correct payer/contractor.

CO-119 Common

Benefit Maximum for Period Reached

Benefit maximum for this time period or occurrence has been reached. The patient has used their full benefit allowance for this service category within the current benefit period.

CO-125 Very Common

Submission or Billing Error

Submission/billing error(s). The claim contains one or more errors that prevent proper adjudication.

CO-129 Less Common

Prior Processing Information Incorrect

Prior processing information appears incorrect. The payer's records from a previous adjudication or processing cycle contain information that conflicts with the current submission.

CO-130 Less Common

Claim Submission Fee

Claim submission fee. This adjustment represents a fee charged by the payer for processing the claim submission.

CO-131 Less Common

Claim Specific Negotiated Discount

Claim specific negotiated discount. This adjustment reflects a negotiated discount applied to this specific claim.

CO-133 Less Common

Service Pending Further Review

The disposition of this service line is pending further review. The payer has not made a final determination and the claim is still under review.

CO-136 Less Common

Failure to Follow Prior Payer Rules

Failure to follow prior payer's coverage rules. The provider did not comply with the primary payer's coverage requirements, affecting the secondary payer's adjudication.

CO-140 Common

Patient ID and Name Mismatch

Patient/Insured health identification number and name do not match. The payer's records show a different name for the submitted member ID, or vice versa.

CO-146 Common

Diagnosis Invalid for Date of Service

Diagnosis was invalid for the date(s) of service reported. The ICD-10 code used was not effective or was terminated on the date the service was rendered.

CO-149 Less Common

Lifetime Maximum for Service Reached

Lifetime benefit maximum has been reached for this service or benefit category. The patient has used their full lifetime allowance for this specific type of service.

CO-151 Common

Frequency or Units Exceeds Limit

Payment adjusted because the payer deems the information submitted does not support this many services or this frequency of services. The number of units or frequency of the service exceeds what the payer considers appropriate.

CO-167 Very Common

Diagnosis Not Covered

This/these diagnosis(es) is/are not covered. The payer does not provide coverage for the submitted diagnosis code.

CO-169 Less Common

Alternate Benefit Provided

Alternate benefit has been provided. The payer has applied payment for a different or substitute service rather than the one billed.

CO-170 Common

Payment Denied for Provider Type

Payment is denied when performed/billed by this type of provider. The payer does not cover this service when rendered by the billing provider's specialty or credential type.

CO-171 Less Common

Denied for Provider Type in Facility

Payment is denied when performed/billed by this type of provider in this type of facility. The combination of provider type and facility setting is not covered.

CO-177 Less Common

Eligibility Requirements Not Met

Patient has not met the required eligibility requirements. The patient does not meet the payer's criteria for coverage eligibility.

CO-178 Less Common

Spend Down Requirements Not Met

Patient has not met the required spend down requirements. The patient's income-based spend down obligation has not been satisfied for the coverage period.

CO-179 Less Common

Waiting Requirements Not Met

Patient has not met the required waiting requirements. A mandatory waiting period must be satisfied before coverage applies for this service.

CO-181 Common

Procedure Code Invalid on Date of Service

Procedure code was invalid on the date of service. The CPT or HCPCS code used was not effective or had been terminated on the date the service was performed.

CO-182 Less Common

Procedure Modifier Invalid on Date of Service

Procedure modifier was invalid on the date of service. The modifier appended to the procedure code was not effective or recognized on the date the service was rendered.

CO-183 Less Common

Referring Provider Not Eligible to Refer

The referring provider is not eligible to refer the service billed. The payer has determined that the referring provider does not have the credentials or authorization to make referrals for this service.

CO-187 Less Common

Consumer Spending Account Payment

Consumer Spending Account payments, including Flexible Spending Account (FSA), Health Savings Account (HSA), and Health Reimbursement Arrangement (HRA). This adjustment reflects a payment made from the patient's consumer spending account.

CO-192 Less Common

Non-Standard Adjustment from Paper Remittance

Non-standard adjustment code from paper remittance. This is a non-standard adjustment that was communicated via a paper remittance advice and does not map to a standard CARC code.

CO-193 Common

Original Payment Decision Maintained

Original payment decision is being maintained. Upon review, the payer has determined that the original claim was processed properly and the payment decision stands.

CO-194 Less Common

Anesthesia by Operating/Attending Physician

Anesthesia performed by the operating physician, the assistant surgeon, or the attending physician. Payment is adjusted because the anesthesia was provided by the surgeon or attending rather than a separate anesthesiologist.

CO-197 Very Common

Precertification/Authorization/Notification Absent

Precertification, authorization, and/or notification was absent. Required approval was not obtained before the service was rendered.

CO-198 Common

Authorization Exceeded

Precertification, notification, authorization, or pre-treatment number of services or period of time exceeded. The services rendered went beyond what was approved in the authorization.

CO-199 Common

Revenue Code and Procedure Code Mismatch

Revenue code and procedure code do not match. The revenue code submitted on the institutional claim is not compatible with the procedure code billed.

CO-204 Common

Service Not Covered Under Patient Plan

This service/equipment/drug is not covered under the patient's current benefit plan.

CO-206 Common

National Provider Identifier Missing

National Provider Identifier (NPI) is missing. The claim does not include a required NPI for the billing, rendering, referring, or ordering provider.

CO-208 Common

National Provider Identifier Not Matched

National Provider Identifier (NPI) is not matched. The NPI submitted does not match the payer's records for the provider or entity.

CO-209 Common

Regulatory Agreement Adjustment

Per regulatory or other agreement, the provider cannot collect this amount from the patient. This adjustment reflects an amount the provider is contractually or legally prohibited from billing to the patient.

CO-210 Common

Late Precertification/Authorization

Payment adjusted because precertification/authorization was not received in a timely fashion. The required authorization or notification was obtained but not within the payer's required timeframe.

CO-211 Common

NDC Not Covered

National Drug Codes (NDC) not eligible for rebate, are not covered, or are otherwise invalid. The drug identified by the submitted NDC is not covered by the payer.

CO-219 Less Common

Based on Extent of Injury

Based on extent of injury. The payment or denial is determined by the documented extent or severity of the injury.

CO-226 Common

Provider Information Not Provided Timely

Information requested from the billing/rendering provider was not provided or was not provided in a timely manner. The payer requested additional information from the provider but did not receive it within the required timeframe.

CO-227 Common

Patient Information Not Provided

Information requested from the patient/insured/responsible party was not provided or was insufficient. The payer requested information from the patient that was not received.

CO-234 Common

Procedure Not Paid Separately (234)

This procedure is not paid separately. The service is considered included in another service or payment and does not qualify for separate reimbursement.

CO-236 Common

Procedure Not Paid Separately

This procedure or procedure/modifier combination is not paid separately. The service is considered incidental to or included in another procedure.

CO-237 Less Common

Legislated/Regulatory Penalty

Legislated/Regulatory Penalty. This adjustment reflects a payment reduction mandated by legislation or regulation as a penalty.

CO-238 Less Common

Claim Spans Ineligible Coverage Period

Claim spans eligible and ineligible periods of coverage. This is the reduction for the ineligible period. The claim includes dates of service when the patient was not covered.

CO-240 Less Common

Diagnosis Inconsistent with Birth Weight

The diagnosis is inconsistent with the patient's birth weight. The ICD-10 code submitted is not compatible with the documented birth weight for neonatal claims.

CO-242 Common

Services Not Provided by Network Provider

Services/procedures not provided by network/primary care providers.

CO-243 Common

Services Not Authorized by Network/PCP

Services not authorized by network/primary care providers. The required referral or authorization from the patient's network or primary care provider was not obtained.

CO-246 Less Common

Non-Payable Reporting Code

This non-payable code is for required reporting only. The code is used for tracking and reporting purposes and does not generate separate payment.

CO-247 Less Common

Institutional Setting Professional Deductible

Deductible for professional service rendered in an institutional setting and billed on an institutional claim. This adjustment applies the deductible to professional charges submitted on an institutional claim form.

CO-250 Less Common

Incorrect Attachment/Documentation Received

The attachment/other documentation that was received was the incorrect attachment/document. The payer received documentation but it was not the documentation that was requested.

CO-252 Common

Additional Documentation Required

An attachment/other documentation is required to adjudicate this claim/service. The payer needs additional information before processing.

CO-253 Very Common

Sequestration Reduction

Sequestration - reduction in federal payment. This adjustment reflects the mandatory across-the-board reduction in Medicare Fee-for-Service payments required by federal sequestration law.

CO-254 Less Common

Dental Plan Benefits Not Available

Claim received by the dental plan, but benefits are not available under this plan. The dental plan acknowledges receipt of the claim but the service is not covered.

CO-255 Less Common

Property & Casualty Claim Pending Litigation

The disposition of the related Property & Casualty claim is pending due to litigation. Payment is held because the associated liability or P&C claim is in litigation.

CO-256 Common

Not Payable Per Managed Care Contract

Service not payable per managed care contract. The payer has determined that this service is not reimbursable under the terms of the managed care contract.

Patient Responsibility (PR)

Amounts that are the patient's responsibility, including deductibles, copays, and coinsurance.

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