CO-B9: Patient Enrolled in Hospice
CO-B9 means the patient is in hospice and this service is considered part of hospice care. Rebill with GW modifier if unrelated to the terminal diagnosis, or coordinate billing through the hospice provider.
What Does CO-B9 Mean?
When paired with Group Code CO, the hospice-related denial is a contractual adjustment. Services for hospice patients related to the terminal illness are the hospice provider's responsibility. The provider absorbs the cost and cannot collect from the patient. Rebill with GW modifier if the service is unrelated to the terminal illness.
CARC B9 indicates the claim was denied because the patient is actively enrolled in a hospice program. When a patient elects hospice, most services related to the terminal illness become the hospice provider's responsibility. Other providers cannot separately bill Medicare or the payer for services that fall within the hospice benefit.
However, services unrelated to the terminal illness can still be billed separately — but they must be billed with the appropriate GW modifier (indicating the service is unrelated to the hospice diagnosis) and a diagnosis code that is not related to the terminal condition. Without this modifier, the payer's system automatically denies claims for patients with an active hospice election.
The most common cause of this denial is that the rendering provider was unaware the patient had enrolled in hospice and billed without the GW modifier. In other cases, the service may genuinely be related to the terminal diagnosis, in which case it should be billed through the hospice provider.
Common Causes
| Cause | Frequency |
|---|---|
| Patient actively enrolled in hospice The patient is currently enrolled in a hospice program and the billed services are considered part of the hospice benefit — only the hospice provider can bill for these services | Most Common |
| Service related to terminal diagnosis The billed service is related to the patient's terminal illness and is therefore the responsibility of the hospice provider, not the attending physician or other provider | Most Common |
| Provider unaware of hospice enrollment The rendering provider was not informed of the patient's hospice enrollment status and billed services that should be billed through the hospice | Common |
| Hospice election period overlap The date of service falls within the patient's hospice election period, during which most Medicare services are covered under the hospice benefit | Common |
| Incorrect billing for unrelated service The service may be unrelated to the terminal illness but was billed without the appropriate modifiers to indicate it is not part of hospice care | Common |
How to Resolve
- Verify hospice status and terminal diagnosis Confirm the patient's hospice enrollment and identify the terminal diagnosis.
- Assess service relationship Determine if the service is related or unrelated to the terminal illness.
- Rebill with GW modifier if unrelated Resubmit with modifier GW and a non-terminal diagnosis code.
- Bill through hospice if related Coordinate with the hospice provider for billing.
- Appeal if GW modifier was used correctly If the claim was denied despite proper modifier usage, appeal with clinical documentation.
If the service is unrelated to the terminal illness, rebill with the GW modifier and appropriate non-terminal diagnosis code. If the claim was denied despite proper modifiers, appeal with clinical documentation demonstrating the service is unrelated to the hospice diagnosis. Include the patient's hospice diagnosis, the service diagnosis, and physician attestation.
Common RARC Pairings
The RARC code tells you exactly what triggered the CO-B9:
| RARC | Description |
|---|---|
| N130 | Alert: You may need to review plan documents or guidelines. Review Medicare hospice benefit guidelines to determine if the service is related or unrelated to the terminal illness → |
| MA130 | Your claim contains incomplete and/or invalid information. Check if the claim needs the GW modifier for services unrelated to the terminal illness → |
How to Prevent CO-B9
- Check hospice enrollment status during patient registration and before rendering services
- Implement automated hospice eligibility verification in your practice management system
- Communicate regularly with hospice providers about shared patients
- Train staff on hospice billing rules and the use of modifiers (GW for unrelated services)
- Verify the patient's hospice election period dates before providing services
Also Filed As
The same CARC B9 may appear with different Group Codes:
Related Denial Codes
Sources
- https://x12.org/codes/claim-adjustment-reason-codes
- https://www.mdclarity.com/denial-code/b9
- https://www.cms.gov/medicare/payment/hospice
- Codes maintained by X12. Visit x12.org for official definitions.