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CO-167 Denial Code: Diagnosis Not Covered

CO-167 means the payer does not cover the diagnosis or diagnoses billed, either in general or for the specific service. It is often tied to a coverage policy that lists which ICD-10-CM codes support a service. Under CO, the provider absorbs the amount unless it is corrected or appealed.

Quick facts

Code
CO-167 (CARC 167)
Status
Active In use since June 30, 2005; last modified July 1, 2017.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider is responsible for the denied amount. For Medicare, patient liability generally requires a valid ABN given before the service.
  • PR (Patient Responsibility): The patient is responsible, for example when a valid advance notice was signed (often with modifier GA on Medicare claims) or the plan excludes the condition and allows patient billing.
Official description
This (these) diagnosis(es) is (are) not covered. Usage: Refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-167 means

CARC 167 reads “This (these) diagnosis(es) is (are) not covered.” The payer looked at the ICD-10-CM codes on the claim and decided they do not qualify for payment. Most often this means the payer has a coverage policy for the service, such as a Medicare LCD or NCD or a commercial medical policy, that lists covered diagnoses, and none of the diagnoses pointed to on the line appear on it.

The usage note points to the 835 Healthcare Policy Identification segment (loop 2110 REF). When present, it names the exact policy used, which tells you which covered diagnosis list to check.

Example: a lab test is billed with a screening diagnosis, but the payer’s policy only covers the test for certain symptoms or conditions. The test is denied CO-167. If the record documents one of the covered conditions and it was simply not coded, a corrected claim resolves it.

Common causes

  • Diagnosis pointer in box 24E points to the wrong diagnosis in box 21, so a covered diagnosis is on the claim but not linked to the line.
  • Nonspecific or unspecified codes used when the policy covers only specific codes.
  • Screening versus diagnostic coding, where a service is covered for symptoms but not for routine screening (or the reverse).
  • Missing secondary diagnoses that establish coverage, such as the underlying condition for a supply or test.
  • Plan exclusions for certain conditions (for example some plans exclude specific diagnoses or treatments entirely).
  • Frequency or coverage policy updates that changed the covered code list.

How to fix it

  1. Find the policy. Check the REF policy identifier and remark codes, then open the LCD, NCD, or payer policy for the service.
  2. Compare the record to the covered diagnosis list. Look for documented conditions that were not coded or coded too generally.
  3. If coding or pointers were wrong, submit a corrected claim (resubmission code 7 in box 22 with the original claim number) with accurate, supported diagnoses and pointers.
  4. If the coding is right and the record supports necessity, file a redetermination, reconsideration, or appeal with the notes and a letter explaining why the service meets policy.
  5. If there was a valid advance notice, confirm the correct modifier was used (for Medicare, GA when an ABN is on file) so liability can shift to the patient.
  6. Otherwise write off the CO amount. Do not bill the patient without a valid notice or plan provision.

How to prevent it

  • Check high-volume services against coverage policies before scheduling, especially labs, imaging, and DME.
  • Code to the highest specificity documented and link each line to the diagnosis that supports it.
  • Issue ABNs or payer-specific waivers when you expect a service may not be covered, following the notice rules exactly.
  • Update coding tools when LCDs and policies change.
  • Scrub claims for diagnosis-to-procedure coverage before submission. The Claims Validator checks claims before they are sent. For more on diagnosis mismatches, see preventable denials.

Specialty notes

Behavioral health claims can see CO-167 when a plan carves out or excludes certain conditions, or when a Z code is used as the primary diagnosis where a clinical diagnosis is required. DME suppliers see it frequently because many DME policies include strict diagnosis requirements.

Remark codes that may appear with CO-167

  • N115 (This decision was based on a Local Coverage Determination (LCD).): The decision was based on a local coverage determination, which lists covered diagnoses for the service.
  • M76 (Missing/incomplete/invalid diagnosis or condition.): A diagnosis is missing, incomplete, or invalid, rather than simply non-covered.
  • N386 (This decision was based on a National Coverage Determination (NCD).): The decision was based on a national coverage determination.
  • MA01 (Alert: If you do not agree with what we approved for these services, you may appeal our decision.): Medicare appeal-rights alert for the redetermination deadline.
  • CO-11 (The diagnosis is inconsistent with the procedure.): The diagnosis is inconsistent with the procedure, a coding mismatch rather than a coverage exclusion.
  • CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): The service was not medically necessary based on the payer's review.
  • CO-146 (Diagnosis was invalid for the date(s) of service reported.): The diagnosis was invalid for the date of service reported.
  • PR-204 (This service/equipment/drug is not covered under the patient's current benefit plan): The service itself is not covered under the benefit plan.
  • CO-96 (Non-covered charge(s).): A general non-covered charge adjustment.

CO-167 FAQ

What is the difference between CO-167 and CO-11?

CO-11 says the diagnosis does not match or support the procedure. CO-167 says the diagnosis is not covered, either for that service or under the plan. In practice payers use them in overlapping ways, so read the remark codes and policy reference.

Can I change the diagnosis to get paid?

Only if the medical record supports a different or more specific diagnosis. Changing codes without documentation is not appropriate and creates compliance risk.

Can I bill the patient for CO-167?

Not under CO. For Medicare, you generally need a valid ABN signed before the service and the correct modifier on the claim for the patient to be liable. Commercial plans have their own notice and waiver rules.

Is CO-167 appealable?

Yes. If the record supports a covered diagnosis, or the policy supports coverage for the patient's condition, appeal with the notes and the policy language. If the diagnosis was simply miscoded, send a corrected claim instead.