CO-167 Denial Code: Diagnosis Not Covered
The CO-167 denial code means the diagnosis (or diagnoses) on the claim is not covered by the payer - the ICD-10 code billed falls outside what the plan or policy covers for that service. It overlaps with CO-50, but where CO-50 frames the problem as medical necessity, CO-167 points squarely at the diagnosis code itself: either the wrong code went on the claim, or the documented condition is genuinely excluded from coverage.
Common Causes
- The billed ICD-10 code is not on the payer's covered-diagnosis list for the service (LCD/NCD or plan medical policy)
- An unspecified or less specific code was billed when the policy covers only specific codes in the family
- The primary diagnosis position holds a code the payer will not accept as primary (for example, certain Z codes or manifestation codes)
- Coding from the problem list instead of the encounter documentation, pulling in a condition unrelated to the service
- The condition is genuinely excluded by the plan (cosmetic, routine, or benefit exclusions)
How to Fix CO-167
- Compare the denied diagnosis against the payer's coverage policy for the billed service and identify which covered codes the documentation would support
- Re-review the encounter note: if a more specific or more accurate ICD-10 code is documented, correct the claim and resubmit
- Check code sequencing - move a covered, supported diagnosis into the primary position when the denial is driven by the primary code
- Confirm every code is billable (leaf-level) and valid for the date of service
- If the documented condition is simply not covered, determine patient responsibility per the plan and your notice obligations before billing anyone
CO-167 is an ICD-10 selection problem more often than a true coverage exclusion. Specificity is the usual culprit: policies list precise codes, and unspecified siblings deny. Validate the claim's diagnosis codes - billable status, specificity, sequencing conflicts - and then re-select against the documentation and the payer's covered list before resubmitting.
Check your codes in the ICD-10 ValidatorFrequently Asked Questions
CO-167 means the diagnosis billed is not covered by the payer for this service. The ICD-10 code on the claim is outside the payer's covered-diagnosis list - because of a coding choice that can be corrected, or a genuine benefit exclusion.
Pull the payer's coverage policy for the service and compare its covered diagnosis codes against the documentation. If the note supports a covered, more specific code, correct and resubmit. If the condition truly is not covered, the claim will not pay under that benefit - handle patient liability per the plan rules.
Both are diagnosis-driven coverage denials. CO-50 says the service was not medically necessary as billed; CO-167 says the diagnosis itself is not covered. In practice both usually mean the ICD-10 codes on the claim did not match the payer's policy, and both are worked by re-checking documentation, specificity, and the covered-diagnosis list.
Related Denial Codes
Related Resources
Claim adjustment reason codes and remittance advice remark codes are standardized code sets maintained by X12. The explanations on this page are written in our own words for educational purposes, based on public CMS and Medicare contractor documentation. Payer policies vary - always confirm handling with the specific payer's guidance and your contracts.