CO B15 denial code

Claim adjustment reason code B15. Often reported as CO B15.

Qualifying service not received

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 B15 means

This service is only paid when another qualifying service is also received and covered, and the payer has no record of it.

Some services are add-ons or depend on a primary service. B15 means the payer cannot find the qualifying service it needs to see before it will pay this one, or the qualifying service has not been processed yet.

If the payer sends a policy reference with the remittance, it identifies the dependency rule it applied.

Group codes seen with B15

On a remittance, B15 comes after a group code. These are the ones it is most often reported with:

• CO B15 (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.

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

• An add-on code was billed without its primary procedure on the same claim.
• The qualifying service was billed by another provider and has not yet been processed.
• The qualifying service was denied, which made the dependent service unpayable too.

What to do next

1. Identify which primary or qualifying service the billed code depends on.
2. Make sure the qualifying service was billed and paid, and resubmit together if needed.
3. Wait for the qualifying claim to finish processing, then ask the payer to reprocess this one.
4. Appeal the qualifying service first if it was denied incorrectly.

Related codes

• B14 (reason code) One visit per physician per day
• A6 (reason code) Prior stay or 30 day transfer rule not met