CO (Contractual Obligation) Denial Codes

CO adjustments mean the payer adjusted the claim based on your contract with them. The provider bears the financial responsibility — you cannot bill the patient for CO adjustments. CO is the most common Group Code in medical billing. These adjustments typically indicate billing errors that need correction and resubmission, fee schedule differences between billed and contracted rates, or coding issues.

Common scenarios: Billing errors that need correction and resubmission. Fee schedule differences between billed and contracted rates. Bundling adjustments where services are not paid separately. Timely filing limit exceeded.

Codes: 281 active Financial responsibility: Provider Patient billable: No
Disclaimer
This content is for informational purposes only. Always verify against your payer contracts and current coding guidelines.

All CO Denial Codes

Code Name Category Action
CO-1 Deductible Amount patient responsibility Review & Decide →
CO-2 Coinsurance Amount patient responsibility Review & Decide →
CO-3 Co-payment Amount other Review & Decide →
CO-4 Procedure Code Inconsistent with Modifier coding error Verify & Resubmit →
CO-5 Procedure Code Inconsistent with Place of Service coding error Verify & Resubmit →
CO-6 Procedure/Revenue Code Inconsistent with Patient Age coding error Verify & Resubmit →
CO-7 Procedure/Revenue Code Inconsistent with Patient Gender coding error Verify & Resubmit →
CO-8 Procedure Code Inconsistent with Provider Type/Specialty coding error Verify & Resubmit →
CO-9 Diagnosis Inconsistent with Patient Age coding error Verify & Resubmit →
CO-10 Diagnosis Inconsistent with Patient Gender coding error Verify & Resubmit →
CO-11 Diagnosis Inconsistent with Procedure coding error Verify & Resubmit →
CO-12 Diagnosis Inconsistent with Provider Type coding error Verify & Resubmit →
CO-13 Date of Death Precedes Date of Service coding error Verify & Resubmit →
CO-14 Date of Birth Follows Date of Service coding error Verify & Resubmit →
CO-16 Missing Information or Billing Error information missing Verify & Resubmit →
CO-18 Exact Duplicate Claim/Service duplicate Review & Decide →
CO-19 Workers' Compensation Claim coverage Resubmit →
CO-20 Liability Carrier Responsible coverage Resubmit →
CO-21 No-Fault Carrier Responsible coverage Resubmit →
CO-22 Coordination of Benefits - Another Payer May Cover coverage Resubmit →
CO-23 Prior Payer Adjudication Impact coverage Review & Decide →
CO-24 Charges Covered Under Capitation/Managed Care fee schedule Review & Decide →
CO-26 Expenses Incurred Prior to Coverage coverage Verify & Resubmit →
CO-27 Expenses Incurred After Coverage Terminated coverage Verify & Resubmit →
CO-29 Timely Filing Limit Expired timely filing Appeal →
CO-31 Patient Cannot Be Identified as Insured coverage Verify & Resubmit →
CO-32 Patient Not Eligible Dependent coverage Verify & Resubmit →
CO-33 Insured Has No Dependent Coverage coverage Verify & Resubmit →
CO-34 No Coverage for Newborns coverage Verify & Resubmit →
CO-35 Lifetime Benefit Maximum Reached coverage Review & Decide →
CO-39 Services Denied at Authorization/Pre-certification authorization Appeal →
CO-40 Charges Do Not Meet Emergent/Urgent Care Qualifications coverage Appeal →
CO-44 Prompt-Pay Discount fee schedule Review & Decide →
CO-45 Charge Exceeds Fee Schedule/Maximum Allowable fee schedule Review & Decide →
CO-49 Non-Covered Routine/Preventive Exam coverage Appeal →
CO-50 Non-Covered Service - Not Medically Necessary coverage Appeal →
CO-51 Non-Covered Pre-existing Condition coverage Appeal →
CO-53 Services by Immediate Relative Not Covered coverage Review & Decide →
CO-54 Multiple Physicians/Assistants Not Covered coverage Appeal →
CO-55 Procedure/Treatment Deemed Experimental/Investigational coverage Appeal →
CO-56 Procedure/Treatment Not Proven Effective coverage Appeal →
CO-58 Inappropriate or Invalid Place of Service coverage Appeal →
CO-59 Multiple/Concurrent Procedure Rules Applied bundling Review & Decide →
CO-60 Outpatient Services Not Covered Near Inpatient Stay bundling Review & Decide →
CO-61 Failure to Obtain Second Surgical Opinion authorization Appeal →
CO-66 Blood Deductible patient responsibility Review & Decide →
CO-69 Day Outlier Amount fee schedule Review & Decide →
CO-70 Cost Outlier Adjustment fee schedule Review & Decide →
CO-74 Indirect Medical Education Adjustment fee schedule Review & Decide →
CO-75 Direct Medical Education Adjustment fee schedule Review & Decide →
CO-76 Disproportionate Share Adjustment fee schedule Review & Decide →
CO-78 Non-Covered Days / Room Charge Adjustment coverage Review & Decide →
CO-85 Patient Interest Adjustment other Review & Decide →
CO-89 Professional Fees Removed from Charges bundling Verify & Resubmit →
CO-90 Ingredient Cost Adjustment fee schedule Verify & Resubmit →
CO-91 Dispensing Fee Adjustment fee schedule Review & Decide →
CO-94 Processed in Excess of Charges fee schedule Review & Decide →
CO-95 Plan Procedures Not Followed authorization Verify & Resubmit →
CO-96 Non-Covered Charges coverage Verify & Resubmit →
CO-97 Bundled Service — Not Paid Separately bundling Review & Decide →
CO-100 Payment Made to Patient/Insured other Review & Decide →
CO-101 Predetermination: Anticipated Payment other Verify & Resubmit →
CO-102 Major Medical Adjustment fee schedule Review & Decide →
CO-103 Provider Promotional Discount fee schedule Review & Decide →
CO-104 Managed Care Withhold fee schedule Review & Decide →
CO-105 Tax Withholding Amount other Review & Decide →
CO-106 Patient Payment Option Not in Effect other Verify & Resubmit →
CO-107 Related or Qualifying Service Not Identified information missing Verify & Resubmit →
CO-108 Rent/Purchase Guidelines Not Met coverage Verify & Resubmit →
CO-109 Claim Not Covered by This Payer other Verify & Resubmit →
CO-110 Billing Date Predates Service Date information missing Verify & Resubmit →
CO-111 Not Covered Unless Provider Accepts Assignment coverage Verify & Resubmit →
CO-112 Service Not Furnished Directly or Not Documented information missing Verify & Resubmit →
CO-114 Procedure/Product Not FDA Approved coverage Verify & Resubmit →
CO-115 Procedure Postponed, Canceled, or Delayed other Verify & Resubmit →
CO-116 Advance Indemnification Notice Requirements Not Met coverage Review & Decide →
CO-117 Transportation to Nearest Facility coverage Verify & Resubmit →
CO-118 ESRD Network Support Adjustment fee schedule Review & Decide →
CO-119 Benefit Maximum Reached coverage Review & Decide →
CO-121 Indemnification Adjustment other Review & Decide →
CO-122 Psychiatric Services Reduction fee schedule Review & Decide →
CO-128 Newborn Services in Mother's Allowance bundling Verify & Resubmit →
CO-129 Prior Processing Information Incorrect information missing Verify & Resubmit →
CO-130 Claim Submission Fee fee schedule Review & Decide →
CO-131 Claim-Specific Negotiated Discount fee schedule Review & Decide →
CO-132 Prearranged Demonstration Project Adjustment other Review & Decide →
CO-133 Service Line Pending Further Review other Review & Decide →
CO-134 Technical Fees Removed bundling Verify & Resubmit →
CO-135 Interim Bills Cannot Be Processed other Verify & Resubmit →
CO-136 Failure to Follow Prior Payer's Coverage Rules other Review & Decide →
CO-137 Regulatory Surcharges, Assessments, or Health-Related Taxes other Review & Decide →
CO-139 Contracted Funding Agreement — Subscriber Employed by Provider other Review & Decide →
CO-140 Patient ID Number and Name Do Not Match information missing Verify & Resubmit →
CO-142 Monthly Medicaid Patient Liability Amount other Review & Decide →
CO-143 Portion of Payment Deferred other Review & Decide →
CO-144 Incentive Adjustment for Preferred Product/Service fee schedule Review & Decide →
CO-146 Diagnosis Invalid for Date of Service coding error Verify & Resubmit →
CO-147 Provider Accepted Reduced Payment from Regulatory Authority other Review & Decide →
CO-148 Information from Another Provider Not Provided or Incomplete information missing Verify & Resubmit →
CO-149 Lifetime Benefit Maximum Reached coverage Review & Decide →
CO-150 Information Does Not Support Level of Service coverage Appeal →
CO-151 Information Does Not Support Frequency of Services coverage Appeal →
CO-152 Information Does Not Support Length of Service coverage Appeal →
CO-153 Information Does Not Support Dosage coverage Appeal →
CO-154 Information Does Not Support Day's Supply coverage Verify & Resubmit →
CO-155 Patient Refused the Service/Procedure other Review & Decide →
CO-157 Service Provided as Result of Act of War coverage Appeal →
CO-158 Service Provided Outside the United States coverage Review & Decide →
CO-159 Service Provided as Result of Terrorism coverage Appeal →
CO-160 Benefit Exclusion: Injury from Excluded Activity coverage Appeal →
CO-161 Provider Performance Bonus fee schedule Review & Decide →
CO-163 Attachment/Documentation Referenced on Claim Not Received information missing Resubmit →
CO-164 Attachment/Documentation Not Received in Timely Fashion timely filing Appeal →
CO-166 Payer's Responsibility Ended Before Service Date coverage Verify & Resubmit →
CO-167 Diagnosis Not Covered coverage Verify & Resubmit →
CO-169 Alternate Benefit Provided coverage Review & Decide →
CO-170 Payment Denied for This Provider Type coverage Verify & Resubmit →
CO-171 Payment Denied for Provider Type in This Facility Type coverage Verify & Resubmit →
CO-172 Payment Adjusted for Provider Specialty fee schedule Verify & Resubmit →
CO-173 Service Not Prescribed by a Physician information missing Resubmit →
CO-174 Service Not Prescribed Prior to Delivery authorization Verify & Resubmit →
CO-175 Prescription Is Incomplete information missing Resubmit →
CO-176 Prescription Is Not Current information missing Resubmit →
CO-177 Patient Has Not Met Required Eligibility Requirements coverage Review & Decide →
CO-178 Patient Has Not Met Spend Down Requirements coverage Verify & Resubmit →
CO-179 Patient Has Not Met Required Waiting Period coverage Review & Decide →
CO-180 Patient Has Not Met Residency Requirements coverage Review & Decide →
CO-181 Procedure Code Invalid on Date of Service coding error Verify & Resubmit →
CO-182 Procedure Modifier Invalid on Date of Service coding error Verify & Resubmit →
CO-183 Referring Provider Not Eligible to Refer information missing Verify & Resubmit →
CO-184 Prescribing/Ordering Provider Not Eligible to Prescribe/Order information missing Verify & Resubmit →
CO-185 Rendering Provider Not Eligible to Perform Service information missing Verify & Resubmit →
CO-186 Level of Care Change Adjustment coverage Appeal →
CO-187 Consumer Spending Account Payment Not Approved coverage Review & Decide →
CO-188 Product/Procedure Not Covered Unless FDA-Recommended coverage Appeal →
CO-189 No Specific Procedure Code for Service Billed coding error Verify & Resubmit →
CO-190 Billing for SNF Qualified Stay Already Covered bundling Review & Decide →
CO-192 Non-Standard Adjustment Code from Paper Remittance other Verify & Resubmit →
CO-193 Original Payment Decision Maintained on Review other Appeal →
CO-194 Anesthesia by Operating/Assistant/Attending Physician bundling Verify & Resubmit →
CO-195 Refund to Erroneous Priority Payer other Review & Decide →
CO-197 Precertification/Authorization/Notification Absent authorization Verify & Resubmit →
CO-198 Precertification/Authorization Limits Exceeded authorization Appeal →
CO-199 Revenue Code and Procedure Code Mismatch coding error Verify & Resubmit →
CO-200 Expenses Incurred During Lapse in Coverage coverage Verify & Resubmit →
CO-201 Patient Responsibility via Set-Aside Arrangement other Review & Decide →
CO-202 Non-Covered Personal Comfort or Convenience Services coverage Appeal →
CO-203 Discontinued or Reduced Service coverage Verify & Resubmit →
CO-204 Service/Equipment/Drug Not Covered Under Benefit Plan coverage Appeal →
CO-205 Pharmacy Discount Card Processing Fee fee schedule Review & Decide →
CO-206 National Provider Identifier - Missing information missing Verify & Resubmit →
CO-207 National Provider Identifier - Invalid Format information missing Verify & Resubmit →
CO-208 National Provider Identifier - Not Matched information missing Verify & Resubmit →
CO-209 Provider Cannot Collect from Patient per Regulatory Agreement other Review & Decide →
CO-210 Pre-Certification/Authorization Not Received Timely authorization Appeal →
CO-211 National Drug Codes (NDC) Not Eligible for Rebate, Not Covered coverage Verify & Resubmit →
CO-212 Administrative Surcharges Not Covered fee schedule Review & Decide →
CO-213 Non-Compliance with Physician Self-Referral Prohibition other Appeal →
CO-215 Based on Subrogation of a Third Party Settlement other Review & Decide →
CO-216 Based on Findings of a Review Organization other Appeal →
CO-219 Based on Extent of Injury other Appeal →
CO-222 Exceeds Contracted Maximum Hours/Days/Units fee schedule Appeal →
CO-223 Mandated Federal/State/Local Law Adjustment other Review & Decide →
CO-224 Patient Identification Compromised by Identity Theft other Verify & Resubmit →
CO-225 Penalty or Interest Payment by Payer other Review & Decide →
CO-226 Provider Information Not Provided or Insufficient information missing Verify & Resubmit →
CO-227 Patient/Insured Information Not Provided or Insufficient information missing Verify & Resubmit →
CO-228 Denied for Failure to Supply Information to Previous Payer information missing Verify & Resubmit →
CO-229 Partial Charge Not Considered Due to Type of Bill 12X other Review & Decide →
CO-231 Mutually Exclusive Procedures bundling Verify & Resubmit →
CO-232 Institutional Transfer Amount fee schedule Review & Decide →
CO-233 Hospital-Acquired Condition or Preventable Medical Error other Appeal →
CO-234 Procedure Not Paid Separately bundling Verify & Resubmit →
CO-235 Sales Tax fee schedule Review & Decide →
CO-236 Procedure/Modifier Not Compatible per NCCI bundling Verify & Resubmit →
CO-237 Legislated/Regulatory Penalty other Review & Decide →
CO-238 Claim Spans Eligible/Ineligible Periods - Ineligible Reduction other Review & Decide →
CO-239 Claim Spans Eligible/Ineligible Periods - Rebill Separately coverage Verify & Resubmit →
CO-240 Diagnosis Inconsistent with Patient's Birth Weight coding error Verify & Resubmit →
CO-241 Low Income Subsidy (LIS) Co-payment Amount other Review & Decide →
CO-242 Services Not Provided by Network/Primary Care Providers coverage Appeal →
CO-243 Services Not Authorized by Network/Primary Care Providers authorization Appeal →
CO-245 Provider Performance Program Withhold fee schedule Review & Decide →
CO-246 Non-Payable Code for Required Reporting Only other Review & Decide →
CO-247 Deductible for Professional Service in Institutional Setting patient responsibility Review & Decide →
CO-248 Coinsurance for Professional Service in Institutional Setting patient responsibility Review & Decide →
CO-249 Claim Identified as Readmission other Appeal →
CO-250 Incorrect Attachment/Documentation Received information missing Verify & Resubmit →
CO-251 Incomplete or Deficient Attachment/Documentation Received information missing Verify & Resubmit →
CO-252 Attachment Required to Adjudicate Claim information missing Resubmit →
CO-253 Sequestration Reduction in Federal Payment fee schedule Review & Decide →
CO-254 Dental Plan Benefits Not Available - Submit to Medical coverage Resubmit →
CO-256 Service Not Payable Per Managed Care Contract coverage Review & Decide →
CO-257 Claim Undetermined During Premium Grace Period (HIX) other Review & Decide →
CO-258 Claim Not Covered - Patient in Custody or Incarcerated coverage Resubmit →
CO-259 Additional Payment for Dental/Vision Service Utilization coverage Verify & Resubmit →
CO-260 Processed Under Medicaid ACA Enhanced Fee Schedule fee schedule Review & Decide →
CO-261 Procedure Inconsistent with Patient History coding error Appeal →
CO-262 Adjustment for Delivery Cost (Pharmaceuticals Only) fee schedule Verify & Resubmit →
CO-263 Adjustment for Shipping Cost (Pharmaceuticals Only) fee schedule Verify & Resubmit →
CO-264 Adjustment for Postage Cost (Pharmaceuticals Only) fee schedule Verify & Resubmit →
CO-265 Adjustment for Administrative Cost (Pharmaceuticals Only) fee schedule Verify & Resubmit →
CO-266 Adjustment for Compound Preparation Cost (Pharmaceuticals Only) fee schedule Verify & Resubmit →
CO-267 Claim/Service Spans Multiple Months other Resubmit →
CO-268 Claim Spans Two Calendar Years other Resubmit →
CO-269 Anesthesia Not Covered for This Procedure coverage Appeal →
CO-270 Medical Plan Benefits Not Available - Submit to Dental coverage Resubmit →
CO-271 Prior Contractual Reductions on Current Payment Schedule other Review & Decide →
CO-272 Coverage/Program Guidelines Were Not Met coverage Appeal →
CO-273 Coverage/Program Guidelines Were Exceeded coverage Appeal →
CO-274 Fee/Service Not Payable — Care Coordination Arrangement coverage Verify & Resubmit →
CO-275 Prior Payer Patient Responsibility Not Covered coverage Review & Decide →
CO-276 Prior Payer Denied Services Not Covered by This Payer coverage Appeal →
CO-277 Claim Undetermined During SHOP Exchange Grace Period other Review & Decide →
CO-278 Performance Program Proficiency Requirements Not Met other Review & Decide →
CO-279 Services Not Provided by Preferred Network Providers coverage Appeal →
CO-280 Medical Plan Benefits Not Available - Submit to Pharmacy coverage Resubmit →
CO-281 Deductible Waived Per Contractual Agreement patient responsibility Review & Decide →
CO-282 Procedure/Revenue Code Does Not Match Type of Bill coding error Resubmit →
CO-283 Attending Provider Not Eligible to Direct Care other Verify & Resubmit →
CO-284 Authorization Valid But Does Not Apply to Billed Services authorization Verify & Resubmit →
CO-285 Appeal Procedures Not Followed other Appeal →
CO-286 Appeal Time Limits Not Met timely filing Appeal →
CO-287 Referral Exceeded authorization Verify & Resubmit →
CO-288 Referral Absent authorization Verify & Resubmit →
CO-289 Dental and Medical Plans Considered - Benefits Not Available coverage Review & Decide →
CO-290 Dental Plan Benefits Not Available - Forwarded to Medical coverage Resubmit →
CO-291 Medical Plan Benefits Not Available - Forwarded to Dental coverage Resubmit →
CO-292 Medical Plan Benefits Not Available - Forwarded to Pharmacy coverage Resubmit →
CO-293 Payment Made to Employer other Review & Decide →
CO-294 Payment Made to Attorney other Review & Decide →
CO-295 Pharmacy Direct/Indirect Remuneration (DIR) Adjustment fee schedule Review & Decide →
CO-296 Authorization Valid But Does Not Apply to Provider authorization Verify & Resubmit →
CO-297 Medical Plan Benefits Not Available - Submit to Vision coverage Resubmit →
CO-298 Medical Plan Benefits Not Available - Forwarded to Vision coverage Resubmit →
CO-299 Billing Provider Not Eligible for Payment other Verify & Resubmit →
CO-300 Medical Plan Benefits Not Available - Submit to Behavioral Health coverage Resubmit →
CO-301 Medical Plan Claim — Submit to Behavioral Health Plan coverage Verify & Resubmit →
CO-302 Precertification/Authorization Time Limit Expired authorization Verify & Resubmit →
CO-303 Prior Payer Patient Responsibility Not Covered for QMB patient responsibility Review & Decide →
CO-304 Medical Plan Claim — Submit to Hearing Plan coverage Verify & Resubmit →
CO-305 Medical Plan Claim — Forwarded to Hearing Plan coverage Review & Decide →
CO-306 Type of Bill Inconsistent with Patient Status information missing Resubmit →
CO-307 Medicare Maximum Fair Price Standard Default Refund Amount fee schedule Review & Decide →
CO-308 Contracted Funding Agreement Adjustment fee schedule Review & Decide →
CO-A0 Patient Refund Amount other Review & Decide →
CO-A1 Claim/Service Denied — Remark Code Required other Resubmit →
CO-A5 Medicare PPS Capital Cost Outlier Amount fee schedule Review & Decide →
CO-A6 Prior Hospitalization or 30-Day Transfer Requirement Not Met coverage Appeal →
CO-A8 Ungroupable DRG coding error Resubmit →
CO-B1 Non-Covered Visits coverage Review & Decide →
CO-B4 Late Filing Penalty timely filing Review & Decide →
CO-B7 Provider Not Certified/Eligible for This Service on This Date coverage Verify & Resubmit →
CO-B8 Alternative Services Available — Should Have Been Utilized coverage Appeal →
CO-B9 Patient Enrolled in Hospice coverage Verify & Resubmit →
CO-B10 Allowed Amount Reduced — Component of Basic Procedure Already Paid bundling Review & Decide →
CO-B11 Claim Transferred to Proper Payer — Not Covered Here coverage Verify & Resubmit →
CO-B12 Services Not Documented in Patient Medical Records information missing Appeal →
CO-B13 Previously Paid — Duplicate Payment duplicate Review & Decide →
CO-B14 Only One Visit/Consultation Per Physician Per Day Covered duplicate Resubmit →
CO-B15 Qualifying Service/Procedure Not Received or Covered authorization Verify & Resubmit →
CO-B16 New Patient Qualifications Not Met coding error Resubmit →
CO-B20 Service Partially or Fully Furnished by Another Provider duplicate Resubmit →
CO-B22 Payment Adjusted Based on Diagnosis coding error Resubmit →
CO-B23 Procedure Not Authorized Per CLIA Proficiency Test coverage Verify & Resubmit →
CO-P1 State-Mandated Requirement — Property and Casualty Only other Review & Decide →
CO-P2 Not Work-Related — Workers' Compensation Not Liable coverage Verify & Resubmit →
CO-P3 Workers' Compensation Case Settled — Patient Responsible via MSA coverage Review & Decide →
CO-P4 Workers' Compensation Claim Non-Compensable coverage Verify & Resubmit →
CO-P5 Reasonable and Customary Fee Adjustment — P&C Only fee schedule Review & Decide →
CO-P6 Adjustment Based on Entitlement to Benefits — P&C Only coverage Verify & Resubmit →
CO-P7 Billed Code Not in Fee Schedule/Database — P&C Only fee schedule Resubmit →
CO-P8 Claim Under Investigation — P&C Only other Review & Decide →
CO-P9 No CPT/HCPCS Code Available — P&C Only coding error Resubmit →
CO-P10 Payment Reduced to Zero Due to Litigation — P&C Only other Review & Decide →
CO-P11 P&C Claim Disposition Pending Due to Litigation other Review & Decide →
CO-P12 Workers' Compensation Jurisdictional Fee Schedule Adjustment fee schedule Review & Decide →
CO-P13 Payment Reduced/Denied Per WC Jurisdictional Regulations coverage Appeal →
CO-P14 Service Included in Another Service Payment — P&C Only bundling Review & Decide →
CO-P15 WC Medical Treatment Guideline Adjustment coverage Appeal →
CO-P16 Provider Not Authorized for WC Treatment in This Jurisdiction coverage Verify & Resubmit →
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Other Group Codes

OA
Other Adjustment
PI
Payor Initiated Reduction
PR
Patient Responsibility