What does CO-167 mean on an Explanation of Benefits?

CO-167 means your insurer says the diagnosis code on the claim is not a covered condition under your plan. It differs from CO-50 (not medically necessary) — CO-167 is a coverage question, not a clinical one. Most CO-167 denials are caused by an imprecise ICD-10 code rather than a genuine gap in coverage.

Can a CO-167 denial be appealed?

Yes. If the diagnosis code was imprecise or incorrect, a corrected claim with a more accurate ICD-10 code often resolves the denial without a formal appeal. If the diagnosis code was accurate and your plan genuinely excludes the condition, a formal appeal can argue that the exclusion is impermissible under federal or state law — particularly for mental health conditions covered under the parity act.

How does CO-167 differ from CO-50 or CO-11?

CO-167 (diagnosis not covered) challenges whether the condition itself is covered by your plan. CO-50 (not medically necessary) challenges whether the service was clinically needed. CO-11 (diagnosis inconsistent with procedure) flags a coding mismatch between the diagnosis and the procedure billed. CO-167 is a plan coverage question; the other two are clinical or coding questions.

What if my diagnosis is actually covered but was coded wrong?

This is the most common cause of CO-167 denials. Ask your provider's billing office to review the ICD-10 code submitted and compare it against your actual documented diagnosis. A more specific code — for example, moving from a general symptom code to a confirmed diagnosis code — frequently resolves the denial when resubmitted.

Can my plan legally exclude a diagnosis?

Some exclusions are lawful — cosmetic procedures, experimental treatments, and certain elective services. Others are not. Under the ACA, plans cannot exclude pre-existing conditions. Under the Mental Health Parity Act, plans cannot exclude mental health diagnoses that have comparable physical health coverage. If your CO-167 denial is for a condition you believe should be covered, request your plan's Summary Plan Description and review the exclusion language.

Who is responsible for a CO-167 denial?

If the diagnosis code was wrong, the provider's billing office is responsible for correcting and resubmitting. If the code was accurate but the plan's exclusion is the issue, you as the member must file an appeal or complaint. CO-167 is a Contractual Obligation code — you generally cannot be billed for the denied amount while a correctable billing error is being resolved.

What does CO-167 mean on an Explanation of Benefits?

CO-167 means your insurer says the diagnosis code on the claim is not a covered condition under your plan. It differs from CO-50 (not medically necessary) — CO-167 is a coverage question, not a clinical one. Most CO-167 denials are caused by an imprecise ICD-10 code rather than a genuine gap in coverage.

Can a CO-167 denial be appealed?

Yes. If the diagnosis code was imprecise or incorrect, a corrected claim with a more accurate ICD-10 code often resolves the denial without a formal appeal. If the diagnosis code was accurate and your plan genuinely excludes the condition, a formal appeal can argue that the exclusion is impermissible under federal or state law — particularly for mental health conditions covered under the parity act.

How does CO-167 differ from CO-50 or CO-11?

CO-167 (diagnosis not covered) challenges whether the condition itself is covered by your plan. CO-50 (not medically necessary) challenges whether the service was clinically needed. CO-11 (diagnosis inconsistent with procedure) flags a coding mismatch between the diagnosis and the procedure billed. CO-167 is a plan coverage question; the other two are clinical or coding questions.

What if my diagnosis is actually covered but was coded wrong?

This is the most common cause of CO-167 denials. Ask your provider's billing office to review the ICD-10 code submitted and compare it against your actual documented diagnosis. A more specific code — for example, moving from a general symptom code to a confirmed diagnosis code — frequently resolves the denial when resubmitted.

Can my plan legally exclude a diagnosis?

Some exclusions are lawful — cosmetic procedures, experimental treatments, and certain elective services. Others are not. Under the ACA, plans cannot exclude pre-existing conditions. Under the Mental Health Parity Act, plans cannot exclude mental health diagnoses that have comparable physical health coverage. If your CO-167 denial is for a condition you believe should be covered, request your plan's Summary Plan Description and review the exclusion language.

Who is responsible for a CO-167 denial?

If the diagnosis code was wrong, the provider's billing office is responsible for correcting and resubmitting. If the code was accurate but the plan's exclusion is the issue, you as the member must file an appeal or complaint. CO-167 is a Contractual Obligation code — you generally cannot be billed for the denied amount while a correctable billing error is being resolved.

CO-167Denial code

You found the right place.

CO-167 Denial Code — Diagnosis Not Covered — What It Means and How to Beat It

CO-167 means the insurer says the diagnosis code on your claim isn't a covered condition under your plan — but this denial is frequently caused by an imprecise ICD-10 code rather than a genuine coverage gap.

Appeal Viability Score High — strong grounds to challenge

Analyze My CO-167 Denial — Free →

No account needed · Results in about 30 seconds · Free to start

CO-167 Is Frequently a Coding Fix, Not a Real Coverage Gap

Because most CO-167 denials trace back to an imprecise or incomplete diagnosis code, they resolve at high rates once a provider's coding team reviews the claim. Cases involving a clear, more-specific ICD-10 code score highest of all.

85–100Miscoded diagnosis — a more specific or complete ICD-10 code resolves it entirely

65–84Miscategorization — diagnosis wrongly flagged as an excluded category

45–64Genuine exclusion dispute — diagnosis is accurate; plan language must be challenged

CO-167 denial Description — What It Means in Medical Billing

The plain English translation — and why the denial is not always what it appears.

"This (these) diagnosis(es) is (are) not covered."

CO-167 means the insurer determined that the diagnosis code — the ICD-10 code describing your condition — submitted on your claim is not a covered condition under your plan. Unlike a procedure-based denial, CO-167 targets the reason given for the service, not the service itself.

What CO-167 does not mean: that your condition is genuinely excluded from coverage. Plans rarely exclude specific medical conditions outright. Far more often, CO-167 happens because the diagnosis code was too vague, a required secondary diagnosis was left off the claim, or the insurer's system mistakenly categorized the diagnosis as work-related, cosmetic, or otherwise excluded.

Because "CO" is a Contractual Obligation code, you generally should not be billed directly while this is being corrected or appealed. That distinction is the foundation of almost every successful CO-167 correction.

CO-167 Denial Reason — Why This Denial Happens and How to Overturn It

A diagnosis code being flagged "not covered" is rarely the final word.

The diagnosis code was too vague or unspecified

Many CO-167 denials happen because the biller used a general, "unspecified" ICD-10 code when a more specific code exists and would have been covered. Insurers' claims systems often reject unspecified codes even when the underlying condition is fully covered under a more precise code — a correction your provider's coder can usually make quickly.

A required secondary diagnosis was left off the claim

Many services require a primary diagnosis plus a supporting secondary code to establish clinical context. If the biller only submitted one code, the system may flag the primary diagnosis alone as non-covered — even though the complete clinical picture fully supports coverage.

The diagnosis was miscategorized by the insurer's system

The insurer's system may have mistakenly assumed a diagnosis relates to an excluded category — such as a work injury or cosmetic condition — when it does not. This is a data-matching error, not a true coverage decision, and is very often reversible once the clinical context is clarified in writing.

What a Winning CO-167 Correction Includes

Four elements that consistently resolve diagnosis-not-covered denials.

Get the exact diagnosis code that was denied

Request the full remittance advice or EOB showing which ICD-10 code(s) triggered the CO-167 denial. You cannot fix what you can't see clearly — this is the first step before contacting anyone else.

Have your provider's coder review the claim

Ask them to check whether a more specific ICD-10 code should have been used, or whether a secondary diagnosis was omitted. This single review resolves the majority of CO-167 denials without any further escalation.

Rule out miscategorization

Confirm the diagnosis wasn't mistakenly flagged as work-related, cosmetic, or otherwise excluded. If it was misclassified, this is a data error the insurer can correct directly — no formal appeal required.

Resubmit or appeal, depending on the finding

If a coding fix is identified, request corrected claim resubmission — this resolves most cases. If the diagnosis is accurate and genuinely excluded, request the specific plan language and challenge it using the same standard applied to any coverage exclusion.

CO-167 Denied? Find Out What's Really Going On — Free.

Upload your denial letter. ClaimCompass identifies whether the diagnosis code needs correcting or whether the exclusion itself is challengeable, and generates the letter you need.

Start My Free Analysis →

Free to analyze · $39 complete appeal · No subscription · All escalation levels included

Still looking

Other codes and appeal guides

You’re in the right place.

Upload the letter. We’ll tell you what it means — free.

No account. About 30 seconds. Plain English, then a clear next step.

Analyze my letter — it’s free How it works

No account. File deleted after your score — and after letter delivery if you purchase.