CO B22 denial code

Claim adjustment reason code B22. Often reported as CO B22 or PR B22.

Adjusted based on the diagnosis

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 B22 means

The payer reduced or denied the line because of the diagnosis codes reported with it.

B22 tells you the diagnosis drove the payment decision. The payer's policy ties coverage or payment for the service to certain conditions, and the diagnosis on the claim did not meet that rule.

Look at the diagnosis pointer as well as the codes themselves: the right code may be on the claim but not linked to the line.

Group codes seen with B22

On a remittance, B22 comes after a group code. These are the ones it is most often reported with:

• CO B22 (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.
• PR B22 (Patient Responsibility): The amount is assigned to the patient. Deductibles, coinsurance and copays are the everyday examples. Whether you can collect it still depends on your contract and the patient's plan.

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 diagnosis on the claim is not one the payer covers for the service.
• The diagnosis pointer linked the line to the wrong diagnosis code.
• A non-specific or unacceptable code was used where the policy requires greater specificity.

What to do next

1. Compare the diagnosis codes and pointers on the claim against the payer's coverage policy for the service.
2. Correct the diagnosis linkage or code from the record and resubmit if billed wrong.
3. Appeal with records if the documented condition supports coverage.

Related codes

• 50 (reason code) Not medically necessary per the payer
• B8 (reason code) A less costly alternative was available
• 16 (reason code) Missing information or billing error