CO B9 denial code

Claim adjustment reason code B9. Often reported as CO B9 or OA B9.

Patient is enrolled in hospice

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What B9 means

The patient was in hospice on the date of service, so this payer will not pay the claim as billed.

When a patient elects hospice, care related to the terminal condition is usually covered through the hospice benefit, and the hospice is responsible for it. B9 means the payer found an active hospice election that overlaps your date of service.

Services unrelated to the terminal illness may still be payable, but often need to be billed with an indicator showing that they are unrelated.

Group codes seen with B9

On a remittance, B9 comes after a group code. These are the ones it is most often reported with:

• CO B9 (Contractual Obligation): The provider's side of the ledger. The reduction comes from the payer contract or a rule the provider has to follow, and the patient normally cannot be billed for it.
• OA B9 (Other Adjustment): Used for adjustments that are neither the provider's contractual write-off nor the patient's share. It often appears with coordination of benefits, for example when another payer already paid.

The payer chooses the group code for each adjustment, so the same reason code can appear with another group code on your remittance. Read the two together. More about group codes.

Common causes

• The patient elected hospice before or during the dates billed.
• The service relates to the terminal diagnosis and should be arranged through the hospice.
• An unrelated service was billed without the indicator or modifier the payer requires.

What to do next

1. Check the patient's hospice election dates and the hospice provider in the payer's eligibility system.
2. Contact the hospice to arrange payment if the service relates to the terminal condition.
3. Resubmit with the payer's unrelated care indicator if the service was not for the terminal illness.

Related codes

• B11 (reason code) Sent to the proper payer
• 109 (reason code) Not covered by this payer, send elsewhere