CO 122 denial code

Claim adjustment reason code 122. Often reported as CO 122 or PR 122.

Reduced for mental health services

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 122 means

The payer reduced payment for this service because a psychiatric payment reduction applies.

Some plans pay outpatient mental health services at a reduced rate, or apply a specific limit to them, compared with other medical services. This code reports that reduction.

The amount and rules depend on the plan and on parity requirements, which have narrowed such reductions over time. Check the plan terms if the reduction looks unexpected.

Group codes seen with 122

On a remittance, 122 comes after a group code. These are the ones it is most often reported with:

• CO 122 (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 122 (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 plan applies a reduced payment rate to outpatient mental health services.
• The service was classed as a psychiatric service under the payer's rules.
• The payer did not update its pricing for current plan terms.

What to do next

1. Confirm the plan's mental health benefit terms for the date of service.
2. Check whether the reduction is consistent with the plan's own rules for medical services.
3. Ask the payer for a review if the reduction appears to be applied in error.

Related codes

• 45 (reason code) Charge exceeds the allowed amount
• 119 (reason code) Benefit maximum reached