Claim adjustment reason code
Denial code CO-B9 meaning
CARC B9, usually seen as CO-B9: The patient is in hospice, so the hospice should be billed for care related to the terminal illness.
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- Reason code
- CARC B9
- Short name
- Patient enrolled in hospice
- Plain meaning
- The patient is in hospice, so the hospice should be billed for care related to the terminal illness.
- Group codes
- CO-B9: Contractual obligation. The provider absorbs the amount under its contract or the payer's rules. Do not bill the patient for it.
Plain-English summary written by Rivvi. X12 owns the CARC list and its exact wording, which is not reproduced here. Read it on the X12 CARC list (list dated November 1, 2025, checked October 23, 2026). This page does not decide how a claim is paid.
Common causes
- The service relates to the hospice diagnosis.
What to check before resubmitting
- Bill the hospice for related care.
- If the care is not related, use the modifier that says so (GW for Medicare) and resubmit.
Related reason codes
Related pages
Questions
What does denial code CO-B9 mean?
The patient is in hospice, so the hospice should be billed for care related to the terminal illness. This is Rivvi's plain-English summary of CARC B9. X12's exact wording is on x12.org.
How do I fix CO-B9?
Bill the hospice for related care. If the care is not related, use the modifier that says so (GW for Medicare) and resubmit.
Can I bill the patient for CO-B9?
With group code CO, no. CO means the provider absorbs the amount under its contract or the payer's rules.
Which group codes come with CARC B9?
Most often CO (contractual obligation). The group code, not the reason code, says who owes the amount.
What is the difference between a CARC and a RARC?
A claim adjustment reason code (CARC) says why a claim line was paid differently than billed. A remittance advice remark code (RARC) adds detail, such as which field is missing.