CO 228 denial code

Claim adjustment reason code 228. Often reported as CO 228 or PR 228.

Info not supplied to a previous payer

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 228 means

The claim was denied because someone, a provider or the subscriber, did not give an earlier payer information it asked for.

This is a coordination of benefits problem. The primary payer denied or held the claim because information was missing, and the secondary payer will not step in until that is resolved.

Fix the primary payer's request first. Once the primary processes the claim, send the secondary claim with the new primary remittance.

Group codes seen with 228

On a remittance, 228 comes after a group code. These are the ones it is most often reported with:

• CO 228 (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 228 (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 primary payer denied for missing records or patient information that was never provided.
• The patient did not answer the primary payer's questionnaire.
• A secondary claim was sent with a primary remittance showing a pending information request.

What to do next

1. Look at the primary remittance to see what information was requested.
2. Send the requested information to the primary payer or help the patient do so.
3. Rebill the secondary payer with the updated primary remittance once it pays or adjusts.

Related codes

• 226 (reason code) Provider did not send requested info
• 227 (reason code) Patient did not send requested info
• 22 (reason code) Another payer may be primary