PR 204 denial code

Claim adjustment reason code 204. Often reported as PR 204 or CO 204.

Not covered under the patient's plan

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 204 means

The patient's current benefit plan does not include this service, equipment or drug, so the payer did not pay for it.

This is a benefit exclusion, not a billing error. The plan simply does not cover what was billed, regardless of medical need or coding.

With group code PR the payer is telling you the patient is responsible, which usually happens when the exclusion is a plan design choice. With CO the provider usually carries the loss, often because the contract or a missing advance notice keeps you from billing the patient. Check the group code before moving any balance.

Group codes seen with 204

On a remittance, 204 comes after a group code. These are the ones it is most often reported with:

• PR 204 (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.
• CO 204 (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

• The service is excluded by the plan, for example certain cosmetic, dental, vision or hearing services.
• The drug is not on the plan's formulary or the equipment is not a covered benefit.
• The patient changed plans and the new plan excludes something the old one covered.
• The procedure was billed under the medical plan but is covered only under a separate rider or plan.

What to do next

1. Confirm the exclusion with the payer's benefit information for this patient and date of service.
2. Check whether the patient has other coverage, such as a dental, vision or pharmacy plan, that could pay.
3. If the group code is PR, confirm any advance notice or waiver on file before billing the patient.
4. Appeal only when the plan documents show the service is covered or the wrong code drove the denial.
5. Add the exclusion to your eligibility checks so patients hear about it before future visits.

Related codes

• 96 (reason code) Service not covered by the plan
• 27 (reason code) Service after coverage ended
• 197 (reason code) No prior authorization on file
• 50 (reason code) Not medically necessary per the payer