CO-167 means the plan does not cover services for the diagnosis on the claim, for example some cosmetic, routine or excluded conditions. First make sure the right diagnosis was coded. If it was, the service is not covered; who pays depends on the group code and any waiver the patient signed.
The official wording
The X12 Claim Adjustment Reason Code list defines 167 as: "This (these) diagnosis(es) is (are) not covered."
The letters in front are the group code. CO means contractual obligation (the provider absorbs it), PR means patient responsibility, and OA is other adjustment. The same reason code can come with different group codes, so always read both.
Common causes
- The diagnosis is an exclusion under the patient's plan.
- A symptom or unspecified code was used when the note supports a covered, specific diagnosis.
- Wrong diagnosis order or pointer.
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How to fix it
- Re-read the note and confirm the diagnosis and its specificity.
- If coding was wrong, send a corrected claim.
- If the diagnosis is excluded, check the group code and any signed waiver before billing the patient.
One claim with a diagnosis the plan does not cover
A patient's plan excludes weight-loss services. The visit is billed with obesity as the only diagnosis.
| Item | On the claim | What it means |
|---|---|---|
| Service | 99214 office visit | Visit itself is a covered service |
| Diagnosis | E66.9 obesity, unspecified (only diagnosis) | Plan excludes care for weight loss |
| Remittance | CO-167 or PR-167 | Diagnosis not covered |
| Fix | Check what the note really treated | If it documents a covered condition, code it first and send a corrected claim |
Only add or move a diagnosis when the note supports it. Changing codes just to get paid is a compliance risk.
CO-167 or a coding problem?
Work out which of these it is before you do anything.
| Situation | What it looks like | What to do |
|---|---|---|
| True plan exclusion | Benefit summary lists the condition as excluded | Write off (CO) or bill the patient (PR) under your policy |
| Unspecified or symptom code | Note supports a specific covered code | Code the specific diagnosis and send a corrected claim |
| Wrong order or pointer | Covered diagnosis is on the claim but not linked to the line | Fix the pointer and send a corrected claim |
| Medicare coverage policy | Test billed with a diagnosis not in the LCD/NCD list | Check the LCD; get an ABN next time if it may not be covered |
For Medicare, a signed ABN before the service lets you bill the patient with modifier GA.
How to fix CO-167
- Read the plan's benefit summary or the Medicare LCD/NCD for the service.
- Re-read the note and code every condition that was treated, most specific first.
- Check that the line's diagnosis pointer points to the covered diagnosis.
- If the note supports a covered diagnosis, send a corrected claim. If not, follow your write-off or patient billing policy.
- Next time, check coverage and get a waiver or ABN before the visit.
CO-167 checklist
- ☐ Diagnosis is coded to the highest specificity the note supports.
- ☐ Pointers link each service to its covered diagnosis.
- ☐ Plan exclusions checked for elective services.
- ☐ ABN signed before Medicare services that may not be covered.
Questions people ask about CO-167
Can I change the diagnosis to get paid?
Only to a code the note supports. Changing a diagnosis just to get coverage is not allowed.
Can I bill the patient for CO-167?
With PR-167, yes. With CO-167, only if your contract and a signed waiver allow it.
Can I add a diagnosis after the denial?
Only if the original note documents it. Never add a diagnosis that is not in the record.
What is the difference between CO-167 and CO-50?
CO-167 says the diagnosis is not covered. CO-50 says the service was not medically necessary for the diagnosis given.
Can I bill the patient for PR-167?
Yes, PR means patient responsibility under the plan. With CO-167, check your contract first.
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PR-1 · PR-2 · PR-3 · CO-4 · CO-5 · CO-11 · CO-15 · CO-16 · OA-18 · CO-22 · OA-23 · CO-24 · CO-26 · CO-27 · CO-29 · CO-31 · CO-45 · CO-49 · CO-50 · CO-59 · PR-96 · CO-97 · CO-109 · CO-119 · CO-129 · CO-140 · CO-146 · CO-151 · CO-167 · CO-170 · CO-181 · CO-185 · CO-197 · CO-198 · PR-204 · CO-234 · CO-236 · CO-242 · CO-252 · CO-253 · CO-288 · CO-A1 · CO-B7 · MA130 · N130 · N23 · N290
Timely filing limits by payer: Cigna timely filing limit · HealthSpring timely filing limit · Aetna timely filing limit · UnitedHealthcare timely filing limit · Humana timely filing limit · corrected claim timely filing limits
Sources: X12 Claim Adjustment Reason Code list (167), read October 12, 2026; CMS Medicare guidance where Medicare rules are mentioned. Last reviewed October 12, 2026. General information, not coding or legal advice. Payer rules differ, so check the remark code and the payer's own policy.