PR B1 denial code

Claim adjustment reason code B1. Often reported as PR B1 or CO B1.

Visits not covered

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 B1 means

The visits on the claim are not a covered benefit under the patient's plan or exceed what the plan covers.

B1 tells you the payer treated the billed visits as non-covered. This can be a plain benefit exclusion, or the patient may have used up the number of visits the plan allows for that type of care.

The group code matters here. With PR the payer is saying the patient is responsible; with CO the provider is held liable, often because of a contract term or missing advance notice.

Group codes seen with B1

On a remittance, B1 comes after a group code. These are the ones it is most often reported with:

• PR B1 (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 B1 (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 plan excludes the type of visit, such as certain therapy or counseling visits.
• The patient reached the annual or per condition visit limit.
• The visit was billed under a benefit category the plan does not cover.

What to do next

1. Check the patient's benefits for the visit type and any visit limits already used this year.
2. Confirm whether a signed financial waiver or notice of non-coverage was collected before the visit.
3. Appeal with medical necessity support if the plan allows extra visits on review.
4. Bill the patient only if the group code and your contract allow it.

Related codes

• 96 (reason code) Service not covered by the plan
• 119 (reason code) Benefit maximum reached
• B14 (reason code) One visit per physician per day