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CO-B1 Denial Code: Non-Covered Visits

CO-B1 means the payer has classified some or all visits on the claim as non-covered. The visits may exceed a benefit limit, fall outside covered visit types, or not meet plan requirements. The group code determines whether the provider or patient carries the cost.

Quick facts

Code
CO-B1 (CARC B1)
Status
Active In use since January 1, 1995.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider absorbs the non-covered visits, often when required notices weren't given or the contract bars patient billing.
  • PR (Patient Responsibility): The patient is responsible, for example when visits exceed the benefit and the patient was told in advance. You may bill the patient under your agreement.
Official description
Non-covered visits.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-B1 means

CARC B1 says non-covered visits. The payer isn’t paying for one or more visits on the claim. It’s an older, general code: it tells you the visits are outside coverage, but not exactly why. Remark codes, the patient’s benefit details, and the payer’s visit counters usually fill in the reason.

The most common scenario is a visit limit. Many plans cap visits per year for services like physical therapy, chiropractic care, or home health. Once the patient uses up their allotment, further visits are non-covered. B1 can also appear when a visit type isn’t a covered benefit at all.

Example: a patient’s plan covers 20 therapy visits a year. The patient had 15 visits at another clinic earlier in the year. Your clinic’s claims for visits 21 onward come back with B1 because the plan’s counter shows the limit reached.

Common causes

  • Annual or per-condition visit limits reached, including visits used at other providers.
  • Visit type excluded by the plan.
  • Authorization covering fewer visits than were delivered.
  • Visits beyond a plan of care that the payer approved.
  • Benefit counters shared across specialties, such as combined PT and OT limits.

How to fix it

  1. Check the remark codes and the patient’s visit counts with the payer.
  2. Confirm limits and what counts toward them, including visits at other providers.
  3. Request more visits through authorization or medical necessity review where the plan allows, then ask for reprocessing.
  4. Appeal if the payer counted visits wrong or applied a limit inconsistent with the plan or parity rules.
  5. Bill the patient only when the payer reports PR and notice requirements were met.

How to prevent it

  • Verify remaining visits before the first appointment and periodically during treatment.
  • Track visits used against authorizations and benefit limits.
  • Tell patients when they’re close to their limit and explain options.
  • Monitor visit denials by payer. An ERA Analyzer can surface B1 trends. See authorization and referral denials.

Specialty notes

PT/OT, chiropractic, home health, and behavioral health practices see B1 most because their benefits are commonly counted in visits.

Remark codes that may appear with CO-B1

  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Points to plan documents describing the visit limit or exclusion.
  • N362 (The number of Days or Units of Service exceeds our acceptable maximum.): The number of days or units of service exceeds the payer's acceptable maximum.
  • PR-119 (Benefit maximum for this time period or occurrence has been reached.): Benefit maximum for the time period or occurrence reached, a common reason visits aren't covered.
  • CO-96 (Non-covered charge(s).): Non-covered charge in general, with a remark explaining why.
  • CO-151 (Payment adjusted because the payer deems the information submitted does not support this many/frequency of services.): The information doesn't support this many services or this frequency.
  • CO-198 (Precertification/notification/authorization/pre-treatment exceeded.): Authorization exceeded, such as more visits than approved.

CO-B1 FAQ

When do payers use B1?

Most often on claims with visit-based benefits, such as therapy, home health, chiropractic, or behavioral health visits, when some visits exceed the plan's limit or aren't covered for other reasons. It can also appear on institutional claims that report visits.

How do I find out why the visits weren't covered?

Check the remark codes and the patient's benefits, including annual visit limits and visits already used. Call the payer if the reason isn't clear.

Can a visit limit be extended?

Some plans allow additional visits with medical necessity review or authorization. Mental health and substance use benefits are also subject to parity rules that limit how plans apply visit limits.

Can I bill the patient for CO-B1?

Not under CO. If the payer reports PR, and you informed the patient in advance where required, you can bill them.