CO-B1: Non-Covered Visits
The non-covered visit is a contractual write-off. The provider absorbs the cost and cannot bill the patient.
What Does CO-B1 Mean?
CO-B1 indicates the non-covered visit is a contractual write-off. Under your participation agreement with the payer, you agreed to certain coverage limitations, and this service falls outside the covered benefits. You must absorb the cost — the patient cannot be billed for the amount. This pairing is common when an in-network provider renders a service that the contract excludes from coverage, or when a coverage determination removes the service from the plan's benefit structure.
When CARC B1 appears on a remittance, the payer is telling you that the specific visit or service billed is not a covered benefit under the patient's insurance plan. This is a broad coverage denial that can apply to many service types — office visits, therapy sessions, specialty consultations, or any encounter that falls outside the plan's benefit structure.
The group code paired with B1 is critical for determining your next action. CO-B1 means the non-covered visit is a contractual obligation where the provider absorbs the cost — typically seen when the provider is in-network and the contract limits what can be billed for non-covered services. PR-B1 means the non-covered visit is the patient's financial responsibility — the patient knew or should have known the service was not covered, and the provider can bill the patient for the full amount.
B1 denials can stem from straightforward plan exclusions (the plan simply does not cover that type of visit) or from more nuanced issues like exceeded benefit limits, missing prior authorization, or incorrect coding that made a covered service appear non-covered. Before accepting the denial, it is worth verifying that the correct procedure code was used and that the service does not fall under a covered benefit category. A simple code correction can sometimes convert a B1 denial into a paid claim.
Common Causes
| Cause | Frequency |
|---|---|
| Service not covered under the plan The specific visit type or service category is explicitly excluded from coverage under the patient's insurance plan — for example, certain wellness visits, alternative therapy sessions, or cosmetic consultations | Most Common |
| Exceeded benefit limits The patient has reached the maximum number of covered visits for this service type within the benefit period (e.g., maximum physical therapy visits, mental health sessions, or chiropractic visits per year) | Most Common |
| Missing prior authorization The visit required prior authorization from the payer and the provider did not obtain it before rendering the service | Common |
| Out-of-network provider The visit was rendered by a provider not contracted with the patient's insurance network, and the plan does not cover out-of-network visits or has limited out-of-network benefits | Common |
| Lack of medical necessity The payer determined that the visit was not medically necessary based on the diagnosis codes submitted or the clinical documentation provided | Common |
| Incorrect procedure or visit type code The wrong CPT or visit type code was billed, causing the payer to classify the visit as non-covered when a different code might have been covered | Occasional |
How to Resolve
Verify whether the service is genuinely non-covered or if a coding or authorization issue caused the denial, then take action based on the group code.
- Verify the non-coverage determination Review your payer contract and the patient's benefit summary to confirm the service is genuinely excluded. If the service should be covered, appeal with supporting evidence.
- Check coding accuracy Verify the procedure code is correct. If a different code would accurately represent the service and is a covered benefit, correct and resubmit.
- Post the contractual write-off If the denial is correct, post the CO-B1 adjustment as a contractual write-off. Do not bill the patient for this amount.
- Flag for contract review If CO-B1 denials for a specific service type are recurring, document the revenue impact and raise the issue during contract renegotiation.
Common RARC Pairings
The RARC code tells you exactly what triggered the CO-B1:
| RARC | Description |
|---|---|
| N130 | Alert: You may need to review plan documents or guidelines to determine coverage restrictions for this service. |
| N386 | This decision was based on the submitted/requested information. |
How to Prevent CO-B1
- Maintain an up-to-date reference of non-covered services by payer so staff can identify non-covered visits before they are rendered
- Check benefit limitations before scheduling services that have known coverage restrictions with specific payers
- Negotiate contract terms that clearly define which visit types are covered and which are excluded
- Use correct CPT codes that map to covered benefit categories when the clinical documentation supports it
General Prevention
- Verify insurance coverage and check remaining benefit limits for the specific visit type before scheduling appointments
- Obtain prior authorization when required by the payer for specific visit types or service categories
- Inform patients in advance if a planned visit may not be covered by their insurance, including an estimate of out-of-pocket costs
- Ensure the correct visit type and procedure codes are used on claims to avoid misclassification as non-covered
- Track visit frequency against benefit limits to proactively notify patients when they are approaching or have reached their maximum covered visits
- Stay current with payer policy changes regarding covered visit types and benefit limitations
Also Filed As
The same CARC B1 may appear with different Group Codes:
Related Denial Codes
Sources
- https://www.mdclarity.com/denial-code/b1
- https://x12.org/codes/claim-adjustment-reason-codes
- Codes maintained by X12. Visit x12.org for official definitions.