AVOIDING MEDICARE CLAIM DENIALS: A DETAILED LOOK AT DENIAL CODES (2024)

Medicare denial codes, also known as Remittance Advice Remark Codes (RARCs) and Claim Adjustment Reason Codes (CARCs), communicate why a claim was paid differently than it was billed. These codes are universal among all insurance companies. Most of the commercial insurance companies the same or similar denial codes. Pay attention to action that you need to make in order for the claims to get paid.

Here are some common Medicare denial codes:

• CO-50: These Charges Are Denied as Non-Covered Services Because This Is Not Deemed A 'Medical Necessity' by The Payer.
  • Action: Review the necessity of the service and the documentation supporting it. If the documentation is satisfactory, you may need to appeal.
• CO-97: The Benefit for This Service Is Included in The Payment/Allowance for Another Service/Procedure That Has Already Been Adjudicated.
  • Action: Cross-verify the services provided. If you find an error, resubmit the claim.
• CO-B15: Payment adjusted because this procedure/service is not paid separately.
  • Action: No action required, as these services are typically bundled into another, more comprehensive service.
• CO-16: Claim/service lacks information or has submission/billing error(s) which is needed for adjudication.
  • Action: Review the claim for any missing or incorrect information and resubmit.
• CO-125: Submission/billing error(s).
  • Action: Identify and correct the billing error, then resubmit the claim.
• CO-96: Non-covered charge(s).
  • Action: Verify if the service is covered under the patient's Medicare plan. If it is, resubmit the claim. If not, bill the patient directly.
• CO-109: Claim not covered by this payer/contractor.
  • Action: Ensure that you are submitting the claim to the correct payer/contractor.
• CO-119: Benefit maximum for this time period or occurrence has been reached.
  • Action: No action required, as the maximum benefits for the patient have been reached for the given time period.
• CO-24: Charges are covered under a capitation agreement/managed care plan.
  • Action: No action is required. The services are paid under a capitation agreement.
• CO-A1: Claim denied charges.
• Action: Review the claim to understand the reason for the denial. If it's an error, correct it and resubmit the claim.

• CO-26: Expenses incurred prior to coverage.
  • Action: Verify the date of service. If the service was indeed provided before the coverage start date, the patient may be responsible for the charge.
• CO-27: Expenses incurred after coverage terminated.
  • Action: Confirm the date of service. If the service was provided after the coverage termination date, the patient may be responsible for the charge.
• CO-29: The time limit for filing has expired.
  • Action: This typically can't be corrected. Claims must be submitted within the timeframe specified by the payer.
• CO-31: The patient cannot be identified as our insured.
  • Action: Verify the patient's identity and insurance details, then resubmit the claim if necessary.
• CO-45: Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.
  • Action: Review the charge amount. If it exceeds the allowable amount, adjust the bill and inform the patient of any balance they may owe.
• CO-58: Treatment was deemed by the payer to have been rendered in an inappropriate or invalid place of service.
  • Action: Confirm the place of service code and resubmit the claim if an error was made.
• CO-81: Procedure has not been authorized by the Benefit Plan.
  • Action: Check the requirements of the patient's plan. You may need to obtain authorization before resubmitting the claim.
• CO-85: This payment is adjusted when performed/billed by this type of provider.
  • Action: Check the provider type and services rendered. Resubmit the claim if an error was made.
• CO-94: This is a duplicate of a claim processed, or to be processed, as a crossover claim.
  • Action: Verify if the claim has already been submitted and processed.
• CO-95: This item conflicts with the payer’s processing rules.
  • Action: Identify the conflict by reviewing the payer's rules and resubmit the claim with necessary adjustments.
• CO-140: Patient/Insured health identification number and name do not match.
  • Action: Verify the patient's information and correct any errors, then resubmit the claim.
• CO-151: Payment adjusted because the payer deems the information submitted does not support this many/frequency of services.
  • Action: Review the frequency and necessity of the services provided. If they're in line with standard care, you may need to provide additional documentation and appeal the decision.
• CO-170: These are non-covered services because this is a pre-existing condition.
  • Action: Check the patient's coverage details. If the condition should not be classified as pre-existing, resubmit the claim with additional information.
• CO-197: Payment adjusted for absence of precertification/authorization.
  • Action: Verify whether prior authorization was required and if so, obtain it before resubmitting the claim.
• CO-204: This service/equipment/drug is not covered under the patient's current benefit plan.
  • Action: Check the patient's coverage details. If the service should be covered, resubmit the claim with additional information or discuss other payment options with the patient.
• CO-223: Adjustment code for mandated federal, state or local law/regulation that is not already covered by another code and is mandated before a new code can be created.
  • Action: Understand the specific mandate and adjust the claim accordingly before resubmitting.
• CO-237: Legislated/Regulatory Penalty.
  • Action: This code indicates that the claim adjustment is the result of a penalty as stipulated by law or regulation. No specific action may be applicable.
• CO-238: Claim spans eligible and non-eligible period of coverage.
  • Action: Separate the claim into two parts, one for the eligible period and one for the non-eligible period, then resubmit.
• CO-243: Services not authorized by network/primary care providers.
  • Action: Verify whether prior authorization was required and if so, obtain it before resubmitting the claim.
• CO-246: This non-payable code is for required reporting only.
  • Action: No specific action needed. This code is used for reporting purposes.
• Remember, these are just examples of denial codes. Each code represents a different reason why a claim might be denied, and the specific details of the claim and the patient's coverage can greatly influence the correct course of action. Always refer to the specific insurer's guidance when addressing these codes.
• CO-252: An attachment/other documentation is required to adjudicate this claim/service.
  • Action: Provide the necessary documentation and resubmit the claim.
• CO-253: Sequestration – Reduction in Federal Spending.
  • Action: No action is required. This code indicates a mandatory reduction in payment due to federal budget constraints.
• CO-16 M79: Missing/incomplete/invalid charge.
  • Action: Review the claim for any missing or incorrect charge information and resubmit.
• CO-18 M80: Duplicate claim/service.
  • Action: Verify if the claim has already been submitted and processed.
• CO-22 M81: This is a work-related injury/illness and thus the liability of the Worker's Compensation Carrier.
  • Action: The claim should be sent to the Worker's Compensation insurance, not Medicare.
• CO-23 M82: The equipment was rented for a 3-month period and the rental price was reached.
  • Action: No action required, as the maximum rental price has been met for the specified period.
• CO-119 N130: Consult plan benefit documents/guidelines for information about restrictions for this service.
  • Action: Check the specifics of the patient's plan and resubmit the claim accordingly, or discuss other payment options with the patient.
• CO-131 N362: The number of Days or Units exceeds our acceptable maximum.
  • Action: Verify the number of units or days of service billed. If it's accurate, you may need to provide additional documentation and appeal.
• CO-151 N640: Exceeds number/frequency approved/allowed within time period.
  • Action: Verify the frequency of the service provided. If it's accurate, you may need to provide additional documentation and appeal.
• CO-197 N95: This provider was not certified/eligible to be paid for this procedure/service on this date of service.
  • Action: Verify the provider's certification status on the date of service. If the provider was eligible, resubmit the claim.
• These codes give reasons for denials, adjustments, or informational messages that might influence the payment of a claim. Please note that the best course of action might vary based on the specifics of the claim and the patient's coverage. Always refer to the specific insurer's guidance when addressing these codes.
• CO-200: The insurance coverage is provided by a Managed Care Plan, and the member should seek care from a Managed Care Provider.
  • Action: Refer the patient to a provider within their Managed Care network, as Medicare will not cover the services of providers outside this network.
• CO-201: The member's plan does not cover this service.
  • Action: Check the patient's coverage details. If the service should be covered, resubmit the claim with additional information or discuss other payment options with the patient.
• CO-202: Non-covered personal comfort or convenience services.
  • Action: Services classified as for personal comfort or convenience are typically not covered. The patient may be responsible for these charges.
• CO-203: Non-covered duplicate radiology film.
  • Action: Duplicate films are not typically covered. Check if the films were necessary and if so, appeal with supporting documentation.
• CO-204: Drug was not FDA-approved for medical condition.
  • Action: Verify the usage of the drug. If it was indeed used for an FDA-approved condition, resubmit the claim with supporting documentation.
• CO-205: Procedure code was invalid on the date of service.
  • Action: Confirm the procedure code and the date of service. If the procedure code was invalid on that date, you may need to correct and resubmit the claim.
• CO-206: National Provider Identifier (NPI) mismatch.
  • Action: Verify the NPI on the claim. If there's an error, correct it and resubmit the claim.
• CO-207: Revenue code is invalid on the date of service.
  • Action: Confirm the revenue code and the date of service. If the revenue code was invalid on that date, you may need to correct and resubmit the claim.
• CO-208: National Drug Code (NDC) invalid on the date of service.
  • Action: Confirm the NDC and the date of service. If the NDC was invalid on that date, you may need to correct and resubmit the claim.
• CO-209: Provider Tax ID/NPI combination is invalid.
  • Action: Verify the Tax ID and NPI on the claim. If there's an error, correct it and resubmit the claim.​
• CO-210: Payment adjusted because pre-certification/authorization not received in a timely fashion.
  • Action: Ensure that pre-certification or authorization is received before the service is provided. If it was received in a timely manner, resubmit the claim with proof.
• CO-211: National Drug Codes (NDC) not eligible for rebate, are not covered.
  • Action: Check the patient's coverage details. The patient may be responsible for these charges.
• CO-212: Payment adjusted as the service/procedure is not paid separately. It is bundled into another service/procedure provided on the same day.
  • Action: No action required, as these services are typically bundled into another, more comprehensive service.
• CO-213: The Medical Review department determined that the service(s) is/are not medically necessary based on the information provided.
  • Action: If you believe the service was medically necessary, you may need to provide additional documentation and appeal the decision.
• CO-214: Workers Compensation claim is under review.
  • Action: Wait for the review process to be completed. There is no immediate action needed.
• CO-215: Your claim has been separated to expedite handling. You will receive a separate notice for the other services reported.
  • Action: No immediate action needed. Wait for the separate notice for the other services.
• CO-216: Payment denied because service/procedure is not authorized in this region or by this payer.
  • Action: Verify the service and the payer. If an error was made, correct it and resubmit the claim.
• CO-217: Payment adjusted because patient has not met the required eligibility, spend down, waiting, or residency requirements.
  • Action: Verify the patient's eligibility and other requirements. If the patient meets the requirements, resubmit the claim with proof.
• CO-218: Payment adjusted due to a qualifying condition related to an Emergency Medical Treatment and Labor Act (EMTALA) violation.
  • Action: Review the specifics of the claim and the EMTALA violation. You may need to provide additional documentation and appeal the decision.
• CO-219: Reserved for national assignment.
• CO-220: The applicable fee schedule/facility-specific Medicare allowable amount for this procedure code at this place of service has not yet been determined by Medicare.
  • Action: Await determination by Medicare. There is no immediate action needed.
• CO-221: National Drug Code (NDC) is not payable under Part B Drug Competitive Acquisition Program (CAP) or is not a valid for Medicare Part B.
  • Action: Confirm if the drug falls under Part B Drug CAP. If it does, recheck the NDC and resubmit the claim.
• CO-222: Payment adjusted as the service was provided as part of a clinical trial.
  • Action: No immediate action needed. Clinical trial services may have different coverage rules.
• CO-223: Adjustment code for mandated federal, state, or local law/regulation that is not already covered by another code and is mandated before a new code can be created.
  • Action: Check the specific mandate and adjust the claim accordingly before resubmitting.
• CO-224: Patient diagnosis for this service line is missing or invalid.
  • Action: Verify the diagnosis code and correct it if necessary, then resubmit the claim.
• CO-225: The new patient qualifications were not met.
  • Action: Review the qualifications for a new patient according to Medicare's guidelines. If the patient does meet these qualifications, you may need to provide additional documentation and appeal the decision.
• CO-226: Information requested from the Billing/Rendering Provider was not provided or was insufficient/incomplete.
  • Action: Provide the necessary information and resubmit the claim.
• CO-227: Information requested from the patient/insured/responsible party was not provided or was insufficient/incomplete.
  • Action: Request the necessary information from the patient and resubmit the claim.
• CO-228: The operating Physician ID Number is missing, incomplete, or invalid.
  • Action: Verify the operating physician's ID number, correct it if necessary, and resubmit the claim.
• CO-229: The attending physician ID number is missing, incomplete, or invalid.
  • Action: Verify the attending physician's ID number, correct it if necessary, and resubmit the claim
• CO-230: The Referring Provider ID Number is missing, incomplete, or invalid.
  • Action: Verify the referring physician's ID number, correct it if necessary, and resubmit the claim.
• CO-231: The Billing Provider's State License Number is missing, incomplete, or invalid.
  • Action: Verify the billing provider's State License Number, correct it if necessary, and resubmit the claim.
• CO-232: The Prior Authorization (PA) number is missing, incomplete, or invalid.
  • Action: Verify the PA number, correct it if necessary, and resubmit the claim.
• CO-233: Services/charges exceed our coverage limits.
  • Action: Verify the services provided and the coverage limit of the patient's policy. If the claim exceeds the limit, the patient may be responsible for the additional amount.
• CO-234: This procedure is not paid separately.
  • Action: No action is required. This code means the procedure in question is bundled into another service or procedure and does not have a separate payment.
• CO-235: This service/procedure requires that a qualifying service/procedure be received and covered.
  • Action: Check if a qualifying service was received and covered. If so, resubmit the claim. If not, the patient may be responsible for the cost.
• CO-236: This procedure or procedure/modifier combination is not compatible with another procedure or procedure/modifier combination provided on the same day according to the National Correct Coding Initiative.
  • Action: Review the claim for any coding errors and correct as necessary. Check the National Correct Coding Initiative for proper coding combinations.
• CO-237: Legislated/Regulatory Penalty.
  • Action: This indicates that the claim adjustment is the result of a penalty as stipulated by law or regulation. No specific action may be applicable.
• CO-238: Claim spans eligible and non-eligible period of coverage.
  • Action: Separate the claim into two parts, one for the eligible period and one for the non-eligible period, then resubmit.
• CO-239: Claim lacks individual lab codes included in the test.
  • Action: Ensure all individual lab codes are included and resubmit the claim.
• CO-240: The diagnosis is inconsistent with the procedure.
  • Action: Verify the diagnosis and procedure codes. If necessary, correct the codes and resubmit the claim.
• CO-241: The date of service is inconsistent with the patient's age.
  • Action: Verify the patient's date of birth and the date of service. If necessary, correct the information and resubmit the claim.
• CO-242: The date of service is inconsistent with the patient's gender.
  • Action: Verify the patient's gender and the service provided. If necessary, correct the information and resubmit the claim.
• CO-243: The services billed are not covered due to the patient's end-stage renal disease (ESRD) entitlement.
  • Action: Check the patient's ESRD entitlement status and resubmit the claim with the necessary documentation.
• CO-244: The service is not covered under the patient's current benefit plan.
  • Action: Check the patient's benefit plan and resubmit the claim with the necessary documentation or discuss alternative payment options with the patient.
• CO-245: The hospital must file the Medicare claim for this inpatient non-physician service.
  • Action: The hospital should submit the claim instead of the individual non-physician provider. Ensure the correct entity is submitting the claim.
• CO-246: This non-payable code is for required reporting only.
  • Action: No action is required. This code is for reporting purposes only and does not affect the payment of the claim.
• CO-247: The subsequent care claim overlaps the global period of a previously submitted claim.
  • Action: Review the global period for the previously submitted claim. If the dates do not overlap, resubmit the claim with the correct dates.
• CO-248: The number of Coinsurance Days has been exhausted.
  • Action: Verify the number of coinsurance days for the patient. The patient may be responsible for additional costs if the coinsurance days have been exhausted.
• CO-249: The requested service is not a covered benefit under this demonstration project.
  • Action: No action is required. This code indicates that the service is not covered under a specific demonstration project.
• CO-250: The claim was received after the filing time limit.
  • Action: Check the date the claim was submitted. If it was filed late, you may not be able to resubmit. Be sure to submit all future claims within the filing time limit.
• CO-251: The attachment or other documentation was not received or was not received timely.
  • Action: Resubmit the claim with the necessary attachments or documentation.
• CO-252: An attachment or other documentation is required to adjudicate this claim.
  • Action: Resubmit the claim with the necessary attachments or documentation.
• CO-253: The physician or other provider was not certified/eligible to be paid for this procedure or treatment on the date of service.
  • Action: Check the provider's certification status on the date of service. If there is an error, correct it and resubmit the claim.
• CO-254: The care provided was outside the United States or as a result of war.
  • Action: No action is required. Medicare generally does not cover services provided outside of the United States or as a result of war.
• CO-255: The billed service is not covered by the payer.
  • Action: Check the patient's coverage details. If the service should be covered, resubmit the claim with additional information or discuss other payment options with the patient.
• CO-256: The patient is responsible for the services because they were not authorized.
  • Action: Check if prior authorization was required for the service. If it was, and you did not get it, the patient may be responsible for the costs.
• CO-257: The patient is over the plan's maximum benefit for the service.
  • Action: Check the patient's coverage details. If the maximum benefit has been reached, the patient may be responsible for additional costs.
• CO-258: The service is not payable per your contractual agreement or fee schedule with the payer.
  • Action: Check your agreement or fee schedule with the payer. If the service is indeed not payable, no further action is needed.
• CO-259: The claim contains incomplete and/or invalid information, and no appeal rights are afforded because the claim is unprocessable.
  • Action: Check the claim for errors and correct them. You may need to resubmit the claim.

• CO-260: Services not covered because the patient is enrolled in a Hospice.
  • Action: Check the patient's status. If they are indeed enrolled in a Hospice, the services may not be covered.
• CO-261: The liability insurance carrier reported a release of information does not exist.
  • Action: Check and verify the information provided by the liability insurance carrier. If necessary, obtain a release of information and resubmit the claim.
• CO-262: The VA adjudicated this claim instead of Medicare.
  • Action: No action is required. This code is for informational purposes only.
• CO-263: The services were provided to a Consumer Directed Personal Assistance Program (CDPAP) patient.
  • Action: Check the patient's status. If they are part of the CDPAP, services may be billed differently.
• CO-264: The physician or other provider may be subject to penalties if billing continues for these services.
  • Action: This code is a warning about potential penalties. Review the services being billed to ensure they are appropriate.
• CO-265: This item or service is not payable under the Medicare program.
  • Action: Check the patient's coverage details. If the service should be covered, resubmit the claim with additional information or discuss other payment options with the patient.
• CO-266: The assistant surgeon is not covered.
  • Action: Check the patient's coverage details. If assistant surgeon services should be covered, resubmit the claim with additional information.
• CO-267: The anesthesia service is not covered.
  • Action: Check the patient's coverage details. If anesthesia services should be covered, resubmit the claim with additional information.
• CO-268: The pathology service is not covered.
  • Action: Check the patient's coverage details. If pathology services should be covered, resubmit the claim with additional information.
• CO-269: The radiation therapy service is not covered.
  • Action: Check the patient's coverage details. If radiation therapy services should be covered, resubmit the claim with additional information.
• CO-270: The radiology service is not covered.
  • Action: Check the patient's coverage details. If radiology services should be covered, resubmit the claim with additional information.
• CO-271: The physical therapy service is not covered.
  • Action: Check the patient's coverage details. If physical therapy services should be covered, resubmit the claim with additional information.
• CO-272: The psychiatric service is not covered.
  • Action: Check the patient's coverage details. If psychiatric services should be covered, resubmit the claim with additional information.
• CO-273: The occupational therapy service is not covered.
  • Action: Check the patient's coverage details. If occupational therapy services should be covered, resubmit the claim with additional information.
• CO-274: The speech therapy service is not covered.
  • Action: Check the patient's coverage details. If speech therapy services should be covered, resubmit the claim with additional information.
• CO-275: The audiology service is not covered.
  • Action: Check the patient's coverage details. If audiology services should be covered, resubmit the claim with additional information.
• CO-276: The ophthalmology service is not covered.
  • Action: Check the patient's coverage details. If ophthalmology services should be covered, resubmit the claim with additional information.
• CO-277: The orthopedic service is not covered.
  • Action: Check the patient's coverage details. If orthopedic services should be covered, resubmit the claim with additional information.
• CO-278: The cardiology service is not covered.
  • Action: Check the patient's coverage details. If cardiology services should be covered, resubmit the claim with additional information.
• CO-279: The outpatient service is not covered.
  • Action: Check the patient's coverage details. If outpatient services should be covered, resubmit the claim with additional information.


• CO-280: The inpatient service is not covered.
  • Action: Check the patient's coverage details. If inpatient services should be covered, resubmit the claim with additional information.
• CO-281: The dental service is not covered.
  • Action: Check the patient's coverage details. If dental services should be covered, resubmit the claim with additional information.
• CO-282: The ambulance service is not covered.
  • Action: Check the patient's coverage details. If ambulance services should be covered, resubmit the claim with additional information.
• CO-283: The podiatry service is not covered.
  • Action: Check the patient's coverage details. If podiatry services should be covered, resubmit the claim with additional information.
• CO-284: The chiropractic service is not covered.
  • Action: Check the patient's coverage details. If chiropractic services should be covered, resubmit the claim with additional information.
• CO-285: The DME (Durable Medical Equipment) service is not covered.
  • Action: Check the patient's coverage details. If DME services should be covered, resubmit the claim with additional information.
• CO-286: The home health service is not covered.
  • Action: Check the patient's coverage details. If home health services should be covered, resubmit the claim with additional information.
• CO-287: The diagnostic service is not covered.
  • Action: Check the patient's coverage details. If diagnostic services should be covered, resubmit the claim with additional information.
• CO-288: The preventive service is not covered.
  • Action: Check the patient's coverage details. If preventive services should be covered, resubmit the claim with additional information.
• CO-289: The major medical service is not covered.
  • Action: Check the patient's coverage details. If major medical services should be covered, resubmit the claim with additional information.
• CO-290: The rehabilitation service is not covered.
  • Action: Check the patient's coverage details. If rehabilitation services should be covered, resubmit the claim with additional information.
• CO-291: The pharmacy service is not covered.
  • Action: Check the patient's coverage details. If pharmacy services should be covered, resubmit the claim with additional information.
• CO-292: The skilled nursing facility service is not covered.
  • Action: Check the patient's coverage details. If skilled nursing facility services should be covered, resubmit the claim with additional information.
• CO-293: The hospice service is not covered.
  • Action: Check the patient's coverage details. If hospice services should be covered, resubmit the claim with additional information.
• CO-294: The emergency service is not covered.
  • Action: Check the patient's coverage details. If emergency services should be covered, resubmit the claim with additional information.
• CO-295: The non-emergency service is not covered.
  • Action: Check the patient's coverage details. If non-emergency services should be covered, resubmit the claim with additional information.
• CO-296: The plan procedures not followed.
  • Action: Verify the procedures for the patient's plan were followed correctly. If not, correct the procedures and resubmit the claim.
• CO-297: The claim/service lacks information which is needed for adjudication.
  • Action: Check the claim for missing information. Add the necessary information and resubmit the claim.
• CO-298: The primary payer's processing of the claim/service for the patient is inconsistent with the coverage rules.
  • Action: Check the rules for the primary payer's coverage. If they have processed the claim incorrectly, contact the primary payer.
• CO-299: The patient's enrollment with the plan was not in effect at the time of service.
  • Action: Check the patient's enrollment dates. If the service was provided when the patient was not enrolled, the patient may be responsible for the cost.


• CO-300: The equipment/drug is not covered under the patient's current benefit plan.
  • Action: Check the patient's benefit plan details. If the equipment or drug should be covered, resubmit the claim with additional information or discuss other payment options with the patient.
• CO-301: The service is not covered under the patient's current benefit plan.
  • Action: Check the patient's benefit plan details. If the service should be covered, resubmit the claim with additional information or discuss other payment options with the patient.
• CO-302: The diagnosis is inconsistent with the procedure.
  • Action: Verify the diagnosis and procedure codes. If necessary, correct the codes and resubmit the claim.
• CO-303: The date of service is inconsistent with the patient's age.
  • Action: Verify the patient's date of birth and the date of service. If necessary, correct the information and resubmit the claim.
• CO-304: The date of service is inconsistent with the patient's gender.
  • Action: Verify the patient's gender and the service provided. If necessary, correct the information and resubmit the claim.
• CO-305: The place of service is inconsistent with the procedure.
  • Action: Verify the procedure and the place where it was performed. If necessary, correct the information and resubmit the claim.
• CO-306: The place of service is inconsistent with the patient's age.
  • Action: Verify the patient's age and the place where the service was provided. If necessary, correct the information and resubmit the claim.
• CO-307: The place of service is inconsistent with the diagnosis.
  • Action: Verify the diagnosis and the place where the service was provided. If necessary, correct the information and resubmit the claim.
• CO-308: The procedure code is inconsistent with the provider type/specialty.
  • Action: Verify the provider's type or specialty and the procedure code. If necessary, correct the information and resubmit the claim.
• CO-309: The patient's age is inconsistent with the diagnosis.
  • Action: Verify the patient's age and the diagnosis. If necessary, correct the information and resubmit the claim.
• CO-310: The patient's gender is inconsistent with the diagnosis.
  • Action: Verify the patient's gender and the diagnosis. If necessary, correct the information and resubmit the claim.
• CO-311: The patient's gender is inconsistent with the procedure.
  • Action: Verify the patient's gender and the procedure. If necessary, correct the information and resubmit the claim.
• CO-312: The length of stay is outside the allowable range.
  • Action: Verify the length of the patient's stay. If necessary, correct the information and resubmit the claim.
• CO-313: The number of days of service is not consistent with the acceptable length of stay.
  • Action: Verify the number of days of service. If necessary, correct the information and resubmit the claim.
• CO-314: The diagnosis is inconsistent with the level of service.
  • Action: Verify the diagnosis and the level of service. If necessary, correct the information and resubmit the claim.
• CO-315: The diagnosis is inconsistent with the patient's age.
  • Action: Verify the diagnosis and the patient's age. If necessary, correct the information and resubmit the claim.
• CO-316: The diagnosis is inconsistent with the patient's gender.
  • Action: Verify the diagnosis and the patient's gender. If necessary, correct the information and resubmit the claim.
• CO-317: The referral was not authorized.
  • Action: Verify if a referral was required and if it was authorized. If necessary, obtain the necessary authorization and resubmit the claim.
• CO-318: The maximum benefit for this time period or occurrence has been reached.
  • Action: Check the patient's coverage details. If the maximum benefit has been reached, the patient may be responsible for additional costs.
• CO-319: The benefit for this service is included in the payment or allowance for another service or procedure that has been performed on the same day.
  • Action: No action is required. This code indicates that the benefit for this service is included in the payment for another service.


• CO-320: Maximum coverage exceeded.
  • Action: Verify patient's coverage details. If the maximum coverage has been reached, the patient may be responsible for the additional costs.
• CO-321: Claim/service lacks information needed for adjudication of this claim/service.
  • Action: Check the claim for missing information. Add the necessary information and resubmit the claim.
• CO-322: Claim/line has been paid. No additional payment is due for this service.
  • Action: No action required. This is an informational message indicating that the claim has been paid in full.
• CO-323: Our records indicate that this dependent is not an eligible dependent as defined.
  • Action: Check the patient's status and ensure they are eligible for coverage under the specific policy. If the status is incorrect, update the information and resubmit the claim.
• CO-324: Duplicate claim/service.
  • Action: Check your records to ensure this claim hasn't been previously submitted. If it is indeed a duplicate, no action is necessary. If not, resubmit with clarification.
• CO-325: The time limit for filing has expired.
  • Action: Claims must be filed within the time limit set by the insurer. If the time limit has expired, the claim may not be covered. Check the insurer's time limit policy for further information.
• CO-326: This is a work-related injury/illness and thus the liability of the Worker's Compensation Carrier.
  • Action: If the claim is indeed related to a work-related injury or illness, it should be submitted to the Worker's Compensation Carrier instead of the Medicare.
• CO-327: The admitting diagnosis is inconsistent with the procedure.
  • Action: Verify the admitting diagnosis and procedure codes. If necessary, correct the codes and resubmit the claim.
• CO-328: This procedure code is not payable. It is for reporting/information purposes only.
  • Action: No action required. This code indicates that the procedure is not payable and is used only for reporting or information purposes.
• CO-329: The provider's location information is incorrect.
  • Action: Verify and update the provider's location information as necessary, then resubmit the claim.
• CO-330: This payment is adjusted when performed/billed by a provider of this specialty.
  • Action: Verify the specialty of the provider. If necessary, correct the information and resubmit the claim.
• CO-331: Patient cannot be identified as our insured.
  • Action: Verify the patient's information and insurance details. If necessary, correct the information and resubmit the claim.
• CO-332: The diagnosis for the service rendered is missing.
  • Action: Verify and include the diagnosis for the service rendered, then resubmit the claim.
• CO-333: The claim lacks the necessary documentation for adjudication.
  • Action: Review the claim to ensure all necessary documents were included. If not, attach the necessary documents and resubmit the claim.
• CO-334: The procedure code and modifier were inconsistent with the provider type/specialty.
  • Action: Verify the provider's type or specialty and the procedure code and modifier. If necessary, correct the information and resubmit the claim.
• CO-335: The procedure code and modifier were inconsistent with the service provided.
  • Action: Verify the service provided and the procedure code and modifier. If necessary, correct the information and resubmit the claim.
• CO-336: The claim is missing the necessary information required for adjudication.
  • Action: Review the claim to ensure all necessary information is included. If not, add the required information and resubmit the claim.
• CO-337: The claim is missing the necessary signature(s).
  • Action: Ensure all necessary signatures are included on the claim. If not, obtain the necessary signatures and resubmit the claim.
• CO-338: The submitted claim lacks the required prior authorization.
  • Action: Verify if a prior authorization was required. If so, obtain the necessary authorization and resubmit the claim.
• CO-339: The patient's eligibility for the billed service(s) is required.
  • Action: Verify the patient's eligibility for the services billed. If necessary, correct the information and resubmit the claim.