What does denial code CO-167 mean?

CO-167 means the diagnosis code (ICD-10-CM code) submitted on the claim is not covered by this payer's policy. The payer is not saying the service was unnecessary (that would be CO-50) — they are saying that the condition described by this specific diagnosis code is excluded from coverage under this plan. The fix depends on why the diagnosis is not covered: wrong code specificity, true policy exclusion, wrong payer for a WC/auto condition, or a misapplied exclusion that can be appealed.

What is the difference between CO-167 and CO-50?

CO-50 (not medically necessary) means the payer agrees the condition exists and is potentially covered, but believes the service billed was not clinically necessary for this patient — typically because the documentation doesn't meet their clinical coverage criteria or LCD. CO-167 means the diagnosis code itself is excluded from coverage — the payer doesn't cover this condition at all under this plan, regardless of how well-documented the service is. CO-167 is a coverage exclusion; CO-50 is a medical necessity determination. The appeals process is different for each.

Can I recode to a different diagnosis to get the claim paid?

Only if the alternative code accurately reflects what is documented in the medical record. You cannot code a different diagnosis solely to obtain payment — that is fraud. However, if the original code was less specific than the documentation supports, or if the documentation actually describes a different but covered condition that you coded incorrectly, correcting the code is appropriate and required. Review the documentation carefully and code to the highest level of specificity that the documentation supports.

Can the patient be billed for a CO-167 denial?

CO-167 carries the CO (Contractual Obligation) group code in most cases, meaning the balance is typically a write-off. However, exceptions exist: if the service is covered but the patient chose a non-covered diagnostic indication (e.g., cosmetic procedure with cosmetic diagnosis), patient billing may be appropriate with pre-notification. If the condition belongs to workers' comp or auto insurance, the patient is not responsible — redirect to the correct payer. Always check your payer contract before billing the patient for a CO-167 balance.

What diagnosis codes commonly trigger CO-167?

Common CO-167 triggers: (1) cosmetic procedure diagnosis codes (rhinoplasty, blepharoplasty, tattoo removal, hair loss); (2) diagnosis codes flagged as workers' comp or occupational conditions; (3) diagnosis codes excluded by a specific LCD (e.g., screening colonoscopy codes when billed with a diagnostic indication that converts it to diagnostic, which has different coverage); (4) non-specific diagnosis codes that are excluded while their more specific counterparts are covered; (5) diagnosis codes for conditions excluded from the specific plan type (e.g., dental conditions on a medical plan, vision conditions on a medical plan); (6) experimental or investigational condition codes.

How do I prevent CO-167 denials?

Prevention requires payer-specific diagnosis coverage checks before billing. For your highest-volume payers and most common procedure codes, maintain a reference list of which diagnosis codes trigger CO-167 vs. which are covered. For procedures with a clear cosmetic vs. medical distinction, document the medical indication explicitly in the chart before the service is rendered. For workers' comp or auto accident conditions, route to the correct payer at registration before the claim is even created. And use the most specific ICD-10-CM code the documentation supports — non-specific codes are more likely to hit exclusion lists.

CO-167 Denial Code: Diagnosis Not Covered — Appeal

CO-167 in plain English

CO-167 means the diagnosis code you submitted describes a condition this plan doesn't cover. Before writing it off: (1) check whether a more specific ICD-10 code for the same documented condition is covered; (2) check whether the condition should go to workers' comp, auto insurance, or the VA instead; (3) check whether the exclusion was correctly applied to this specific patient. Recoding (when accurate), redirecting, or appealing a misapplied exclusion are all legitimate paths — upcoding is not.

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Never recode a diagnosis solely to obtain payment — only code what the documentation supports

If the original code accurately reflects the documented condition and the condition is genuinely excluded from coverage, the correct action is appeal or write-off — not upcoding to a covered diagnosis. Changing a diagnosis code to a covered one without clinical documentation to support that code is fraud. The review question is always: "Does the documentation support this alternative code?" — not "Does this code get paid?"

CO-167 vs CO-50 — Critical Distinction

How CO-167 and CO-50 differ — and why the fix process is completely different

CO-167 — Diagnosis Not Covered

The ICD-10 code itself is excluded from the plan's benefit structure
Coverage exclusion — applies regardless of clinical necessity
The payer isn't evaluating whether the service was needed
Fix paths: recode if inaccurate, redirect to WC/auto, appeal misapplied exclusion
Peer-to-peer review is NOT the fix — no clinical argument changes a coverage exclusion
Examples: cosmetic dx codes, workers' comp injury dx, excluded dental/vision dx on medical plan

CO-50 — Not Medically Necessary

The diagnosis may be covered, but documentation doesn't justify the service for this patient
Medical necessity determination — clinical criteria not met
The payer is evaluating whether the service was appropriate for this clinical scenario
Fix paths: appeal with clinical documentation, peer-to-peer review, LCD/NCD citation
Peer-to-peer with the medical director is the strongest appeal path
Examples: MRI for back pain without conservative care, colonoscopy before recommended age

7 Common CO-167 Scenarios

Why CO-167 happens — and the correct action for each

Scenario	Why the Dx Is Not Covered	Action	What to Do
Non-specific ICD-10 code — a more specific code is covered	Payer excludes placeholder or non-specific codes (e.g., M54.5 Low back pain NOS) when more specific codes for the same condition are covered. Many payers require a specific cause code, not a symptom-level code.	Recode	Review documentation for a more specific code (e.g., M51.16 Intervertebral disc degeneration, lumbar region). If the documentation supports the specific code, recode and resubmit. Do not add specificity the documentation doesn't support.
Cosmetic procedure with cosmetic diagnosis	Services primarily for appearance improvement are excluded from most health plan benefit structures. Diagnosis codes that indicate cosmetic indication (e.g., excess eyelid skin for cosmetic reasons, hair restoration) trigger CO-167.	Appeal or Write Off	If the procedure is reconstructive (functional impairment, post-mastectomy, post-trauma), appeal with documentation showing medical indication — not cosmetic intent. If truly cosmetic, write off; the patient may be billed if they were pre-notified.
Work-related injury or occupational illness	Health plans exclude conditions arising from employment. Diagnosis codes for occupational injuries, repetitive stress from work activities, and occupational exposures trigger CO-167 when billed to group health.	Redirect to WC	File with the patient's workers' compensation carrier. Do not bill the patient for a work-related condition — WC is the correct primary payer. If WC denied the injury claim, document the denial and then consider health plan billing with WC denial attached.
Auto accident / motor vehicle injury	Injuries from auto accidents are typically covered by no-fault/PIP auto insurance first. Health plans may exclude auto accident diagnoses (injury codes S/T ICD-10 categories with external cause) or require auto insurance to be exhausted first.	Redirect to Auto Insurance	Bill the patient's auto insurance or no-fault PIP first. Once auto coverage is exhausted or denied, health plan may accept as secondary with the auto payer's EOB attached.
Dental condition billed on medical plan	Medical health plans exclude dental conditions (dental caries, periodontal disease, tooth extractions) except in specific medically necessary circumstances. Dental diagnoses on medical claims generate CO-167.	Redirect to Dental Plan or Appeal	If the patient has a separate dental plan, redirect. If the dental procedure was medically necessary and an exception applies (e.g., dental extractions required before cardiac surgery), appeal with physician documentation of medical necessity.
Excluded condition category under plan design	Some plans exclude specific condition categories: infertility treatment, weight loss/obesity management, sexual dysfunction, sleep disorders (in some plans), and certain mental health conditions in non-MHPAEA-compliant plans.	Appeal or Write Off	Check the plan's Summary of Benefits and Coverage for explicit exclusions. If infertility treatment is excluded but the underlying diagnosis (endometriosis, PCOS) is covered when treated for non-infertility reasons, appeal with documentation of the covered clinical indication.
ICD-10 code not on LCD's covered diagnosis list	For Medicare, many procedures have LCD-based covered diagnosis lists. If the submitted diagnosis is not on the LCD's covered diagnosis list for this procedure, Medicare issues CO-167 even if the condition seems clinically related.	Recode or Appeal	Pull the relevant LCD and compare the submitted code to the covered diagnosis list. If a more specific or differently worded code on the LCD list accurately describes the patient's condition, recode. If the submitted code is accurate and the LCD is being misapplied, appeal with clinical documentation and LCD citation.

Step-by-Step Response

What to do when you see CO-167

Identify which diagnosis code triggered the denial and why it is not covered
Read the remittance advice — CO-167 may apply to a specific line, not the entire claim. Note the exact ICD-10-CM code flagged. Look up the payer's coverage policy, the relevant LCD/NCD for the procedure, or the plan's excluded diagnosis list to understand precisely why this code was denied. The reason determines your path: recode, redirect, appeal, or write off.
Review the medical record — can the documentation support a more specific or different accurate code?
This is the most important step. Read the documentation and ask: "Is the submitted code the most accurate and specific code the documentation supports?" If a more specific ICD-10 code — one that is covered by this payer for this procedure — accurately describes what is documented, correct the code and resubmit. The standard: code to the highest level of specificity the documentation supports, not to whatever gets paid. If the original code was accurate, do not change it.
Check whether the condition belongs to a different payer
If the diagnosis is an injury code (S/T categories), check whether the injury is work-related (redirect to workers' comp) or auto/accident-related (redirect to no-fault/liability). If the diagnosis is a service-connected condition and the patient is a veteran, the VA may be the correct payer. Redirecting to the correct payer is not the same as upcoding — you are routing the claim to the entity responsible for this type of condition.
Appeal if the exclusion was misapplied to this patient's specific situation
Some exclusions have clinical exceptions. A cosmetic exclusion may not apply to a reconstructive procedure for functional impairment. A dental exclusion may not apply to dental care that is a necessary precursor to covered medical treatment. A fertility exclusion may not apply when the underlying diagnosis is a covered condition being treated for non-fertility reasons. Document the specific exception that applies to this patient and cite the plan language or LCD that supports it.
Write off if genuinely not covered and update prevention systems
If the diagnosis is accurately coded, belongs to this payer, and the exclusion correctly applies with no exception — write off the balance. Document the reason: which diagnosis code, which payer, which exclusion policy. Add this diagnosis-payer combination to your pre-billing reference list so future claims with the same code and payer trigger a review before submission, not a denial after.

Appeal Letter

When a cosmetic or categorical exclusion was misapplied

VIA: Appeals Department — Diagnosis Coverage Appeal

Date: [Date] | Payer: [Payer Name] | Claim #: [Claim #]

Member ID: [Member ID] | Patient: [Name] | DOS: [Date of Service]

Provider NPI: [NPI] | Denied Code: CO-167 | Denied ICD-10: [Code]

RE: Appeal of CO-167 Denial — Diagnosis Coverage Exception

This claim was denied under CO-167 indicating that diagnosis code [ICD-10 code] is not covered under this plan. We respectfully appeal this determination on the grounds that [select applicable]:

Option A — Reconstructive exception to cosmetic exclusion:
The denied service was performed for [functional impairment / post-mastectomy reconstruction / correction of congenital defect / treatment of traumatic injury], not for cosmetic improvement. The Women's Health and Cancer Rights Act (WHCRA) requires coverage for breast reconstruction following mastectomy. The documentation enclosed demonstrates the medical indication clearly distinguishes this case from elective cosmetic procedures.

Option B — Covered underlying condition, not excluded indication:
While this plan excludes [infertility treatment / weight management / etc.], the documented clinical indication for this service is [covered condition: PCOS / endometriosis / bariatric surgery for BMI >40 with comorbidities / etc.], which falls within your covered benefit structure. The enclosed medical records document the covered clinical indication as the primary reason for this service.

Option C — LCD covered diagnosis list — documentation supports a covered code:
After review of Local Coverage Determination [LCD number], we have identified that the patient's documented condition is accurately described by ICD-10 code [covered code], which appears on the LCD's covered diagnosis list. We are resubmitting the corrected claim under separate cover.

Enclosed: [medical record / operative note / physician letter / plan exclusion language / LCD / relevant clinical literature].

Contact: [Name, Phone] | Practice: [Practice Name]

Prevention

How to prevent CO-167 before the claim is submitted

Maintain a payer-specific diagnosis coverage reference for your top procedure codes. For each of your highest-volume procedures, document which diagnosis codes each major payer covers and which they exclude. When a claim is coded with a diagnosis-procedure combination that has historically triggered CO-167, flag it for review before submission. This reference builds over time as you collect denial data.
Always code to the highest level of specificity the documentation supports. Non-specific codes are disproportionately represented on payer exclusion lists. A code like M54.5 (Low back pain, unspecified) is more likely to be excluded than M51.16 (Intervertebral disc degeneration, lumbar region). Document specificity at the point of care so that the most precise code can be applied at billing.
Ask about injury mechanism at registration — route WC and auto conditions at intake, before the claim is created. A brief intake question — "Is this visit related to a work injury, auto accident, or other accident?" — routes the claim to the correct payer before it ever hits a health plan that will CO-167 it. This question should be on every intake form and at every front-desk check-in.
For procedures with a cosmetic vs. medical indication distinction, document the medical indication explicitly before the service. Blepharoplasty, panniculectomy, rhinoplasty, and similar procedures can be either cosmetic or medically necessary depending on documentation. Before scheduling, document the functional impairment (visual field obstruction, skin fold infection, breathing impairment) explicitly in the chart. The documentation at time of service determines whether the claim will be covered or CO-167'd.
For Medicare LCD-covered procedures, pull the covered diagnosis list before the service and verify the patient's diagnosis is on it. Many providers learn which diagnoses are on an LCD's covered list only after a CO-167 denial. Proactive LCD review at pre-authorization or scheduling — for procedures with known LCD restrictions — eliminates this surprise entirely.

Frequently Asked Questions: CO-167

CO-167 means the diagnosis code (ICD-10-CM) submitted on the claim describes a condition excluded from coverage under this plan. The payer is not evaluating whether the service was necessary — they are saying the condition itself is not a covered benefit. Fix options: recode if a more specific accurate code is covered, redirect to workers' comp or auto insurance if applicable, appeal if the exclusion was misapplied.

CO-50 (not medically necessary) means the condition may be covered but the documentation doesn't justify this service for this patient. CO-167 means the diagnosis code describes a condition the plan doesn't cover regardless of clinical necessity. CO-167 is a coverage exclusion; CO-50 is a medical necessity determination. Peer-to-peer appeals work for CO-50; they rarely work for CO-167.

Only if the alternative code accurately reflects what is documented. You cannot change a diagnosis to obtain payment — that is fraud. However, if the original code was less specific than the documentation supports, or if an alternative code more precisely describes the documented condition and that code is covered, correcting to the accurate code is appropriate and required. The test: "Does the documentation support this code?" — not "Does this code get paid?"

CO-167 is a CO (Contractual Obligation) denial, generally a provider write-off. However, if the patient chose a non-covered service (e.g., cosmetic procedure) knowing it wasn't covered, and signed a pre-service financial consent acknowledging the non-covered status, you may bill the patient. If the condition belongs to WC or auto insurance, the patient is not responsible — redirect to the correct payer.

Common triggers: cosmetic procedure diagnosis codes; work-related injury S/T codes when billed to health plan; auto accident injury codes; dental diagnosis codes on medical plans; non-specific ICD-10 codes where more specific covered codes exist; infertility diagnosis codes when infertility treatment is excluded; diagnosis codes not on an LCD's covered list for a specific Medicare procedure.

Maintain a payer-specific dx coverage reference, code to the highest documentation-supported specificity, ask about injury mechanism at intake to route WC/auto claims correctly, document medical indication for cosmetic-vs-medical procedures before the service, and check LCD covered diagnosis lists before scheduling Medicare patients for LCD-restricted procedures.

Related Codes

Diagnosis Not Covered by This Payer