Comprehensive ReferenceUpdated 2026
100 Most Common Medical Billing Denials
The complete reference guide to the most frequent denial codes in medical billing. Search, filter, and master CO, PR, and OA codes with detailed resolution strategies.
100 denial codesFrequency rankingsImpact levelsResolution guides
Showing 85 of 85 denials
Complete Denial Code Reference
Click any row to expand details and resolution strategies.
| Code | Category | Frequency | Impact | Description |
|---|---|---|---|---|
| CO-16 | Authorization | Very High | High | Claim/service lacks information or has submission/billing error. |
| CO-45 | Non-Covered | Very High | Medium | Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement. |
| CO-50 | Medical Necessity | Very High | High | These are non-covered services because this is not deemed a "medical necessity" by the payer. |
| CO-97 | Bundled | Very High | Medium | The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated. |
| CO-96 | Bundled | High | Medium | See detailed page |
| CO-11 | Authorization | High | High | The diagnosis is inconsistent with the procedure. |
| CO-22 | Network | High | Medium | This care may be covered by another payer per coordination of benefits. |
| CO-29 | Timely Filing | High | High | The time limit for filing has expired. |
| CO-4 | Authorization | High | High | The service is inconsistent with the modifier used. |
| CO-18 | Duplicate | High | Low | Exact duplicate claim/service. |
| CO-15 | Authorization | Medium | High | The authorization number is missing, invalid, or does not apply to the billed services. |
| CO-19 | COB | Medium | Medium | Claim is covered by a Workers Compensation plan. |
| CO-24 | COB | Medium | Medium | Charges are covered under a capitation agreement/plan. |
| CO-27 | Missing Info | Medium | Medium | Expenses incurred after coverage terminated. |
| CO-30 | Authorization | Medium | High | See detailed page |
| CO-31 | Certification | Medium | High | See detailed page |
| CO-32 | Network | Medium | Medium | See detailed page |
| CO-35 | Utilization Review | Medium | Medium | See detailed page |
| CO-36 | Non-Covered | Medium | Medium | See detailed page |
| CO-38 | Non-Covered | Medium | Medium | Services not provided by network/primary care providers. |
| CO-42 | Workers Comp | Medium | Medium | See detailed page |
| CO-43 | Provider | Medium | Medium | See detailed page |
| CO-44 | Multiple | Medium | Low | See detailed page |
| CO-49 | Benefits | Medium | Medium | See detailed page |
| CO-53 | Medicare | Medium | Medium | See detailed page |
| CO-55 | Benefits | Medium | Medium | See detailed page |
| CO-57 | Missing Info | Medium | Medium | Service(s) not covered under this plan. |
| CO-58 | Benefits | Medium | Medium | See detailed page |
| CO-59 | Missing Info | Medium | Medium | See detailed page |
| CO-74 | Benefits | Medium | Medium | See detailed page |
| CO-76 | Duplicate | Medium | Low | See detailed page |
| CO-77 | Duplicate | Medium | Low | See detailed page |
| CO-80 | Missing Info | Medium | Medium | See detailed page |
| CO-81 | Missing Info | Medium | Medium | See detailed page |
| CO-83 | Provider | Medium | Medium | See detailed page |
| CO-85 | Bundled | Medium | Low | See detailed page |
| CO-86 | Bundled | Medium | Low | See detailed page |
| CO-91 | Duplicate | Medium | Low | See detailed page |
| CO-94 | Missing Info | Medium | Medium | See detailed page |
| CO-95 | Authorization | Medium | High | See detailed page |
| CO-104 | Missing Info | Medium | Medium | See detailed page |
| CO-105 | Provider | Medium | Medium | See detailed page |
| CO-109 | Plan Coverage | Medium | Medium | Claim/service not covered by this payer/contractor. You must send the claim/service to the correct payer/contractor. |
| CO-119 | Benefits | Medium | Medium | Benefit maximum for this time period or occurrence has been reached. |
| CO-120 | HMO | Medium | Medium | See detailed page |
| CO-127 | Missing Info | Medium | Medium | See detailed page |
| CO-130 | Missing Info | Medium | Medium | See detailed page |
| CO-131 | Contract | Medium | Medium | See detailed page |
| CO-140 | Patient Death | Low | Medium | See detailed page |
| CO-141 | Missing Info | Low | Medium | See detailed page |
| CO-142 | Missing Info | Low | Medium | See detailed page |
| CO-149 | Missing Info | Low | Medium | See detailed page |
| CO-151 | Missing Info | Low | Medium | Payment adjusted because the payer deems the information submitted does not support this level of service. |
| CO-155 | Missing Info | Low | Medium | See detailed page |
| CO-157 | Missing Info | Low | Medium | See detailed page |
| CO-167 | Benefits | Low | Medium | See detailed page |
| CO-170 | Authorization | Low | High | See detailed page |
| CO-176 | State Law | Low | Medium | See detailed page |
| CO-180 | Missing Info | Low | Medium | See detailed page |
| CO-186 | Provider | Low | Medium | See detailed page |
| CO-187 | Provider | Low | Medium | See detailed page |
| CO-188 | Provider | Low | Medium | See detailed page |
| CO-189 | Provider | Low | Medium | See detailed page |
| CO-190 | Missing Info | Low | Medium | See detailed page |
| CO-191 | Prescription | Low | Medium | See detailed page |
| CO-193 | Missing Info | Low | Medium | See detailed page |
| CO-195 | Missing Info | Low | Medium | See detailed page |
| CO-196 | Non-Covered | Low | Medium | See detailed page |
| CO-197 | Authorization | Low | High | Precertification/authorization/notification absent. |
| CO-198 | Duplicate | Low | Low | Precertification/authorization absent. |
| CO-204 | Benefits | Low | Medium | See detailed page |
| PR-1 | Deductible | Very High | High | Deductible amount — patient responsibility. |
| PR-2 | Coinsurance | Very High | High | Coinsurance amount — patient responsibility. |
| PR-3 | Copayment | Very High | High | Co-payment amount — patient responsibility. |
| PR-96 | Non-Covered | High | Medium | Non-covered charge(s) — patient responsibility. |
| PR-204 | Non-Covered | Medium | Medium | This service/equipment/drug is not covered under the patient's current benefit plan — patient responsibility. |
| PR-26 | Missing Info | Medium | Medium | See detailed page |
| PR-27 | Missing Info | Medium | Medium | See detailed page |
| PR-49 | Benefits | Medium | Medium | See detailed page |
| PR-94 | Missing Info | Medium | Medium | See detailed page |
| PR-119 | Benefits | Low | Medium | See detailed page |
| OA-18 | Duplicate | High | Low | Exact duplicate claim/service. |
| OA-23 | Missing Info | Medium | Medium | The impact of prior payer(s) adjudication including payments and/or adjustments. |
| OA-94 | Missing Info | Medium | Medium | Processed in excess of charges. |
| OA-109 | Missing Info | Low | Medium | Claim/service not covered by this payer/contractor. You must send the claim/service to the correct payer/contractor. |
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