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CO-B5 Denial Code (Deactivated): Program Guidelines

CO-B5 meant the claim did not satisfy the plan's coverage or program guidelines, or went beyond them. X12 deactivated it and its notes name CARC 272 and CARC 273 as replacements.

X12 deactivated CARCB5 on May 1, 2016. Payers should no longer use it on new remittances, but it can still appear on older ERAs, corrected claims, and appeals.

Code: CO-B5 (CARC B5)
Status: Deactivated StoppedMay 1, 2016 (in use since January 1, 1995).
Code set: Claim Adjustment Reason Codes (CARC)
Group codes: CO (Contractual Obligation): The provider absorbed the amount unless it could show the guidelines were met.
PR (Patient Responsibility): Some payers assigned it to the patient when the plan's program rules placed the cost on the member.
Official description: Coverage/program guidelines were not met or were exceeded.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What CO-B5 meant

CARC B5 was a broad code for claims that fell outside the plan’s coverage or program guidelines. That might mean the patient did not meet the clinical criteria for a service, or that the service exceeded a program limit such as a number of sessions. It was in use for many years before X12 split it.

What replaced it

X12’s notes say it was replaced by codes 272 and 273:

CO-272: coverage or program guidelines were not met.
CO-273: coverage or program guidelines were exceeded.

Related active codes include CO-50 for medical necessity and PR-119 for benefit maximums.

If you still see CO-B5

It remained active until fairly recently, so older claims in A/R or appeals may still carry it. Identify the guideline the payer applied, check the documentation against its criteria, and appeal with records that address each one if you believe they were met. If the service simply exceeded a limit, confirm whether an exception or additional authorization is available.

CO-272 (Coverage/program guidelines were not met.): Named replacement: coverage or program guidelines were not met.
CO-273 (Coverage/program guidelines were exceeded.): Named replacement: coverage or program guidelines were exceeded.
CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): Not deemed a medical necessity by the payer.
PR-119 (Benefit maximum for this time period or occurrence has been reached.): Benefit maximum for the period or occurrence has been reached.

CO-B5 FAQ

Which replacement code applies?

If the claim failed to meet the program's criteria, it is CARC 272. If it met them but went beyond an allowed amount, frequency, or duration, it is CARC 273.

How do I find the guideline that was applied?

Look for a remark code or a policy reference on the remittance, and ask the payer for the specific coverage policy. Appeals are strongest when they address the exact criteria.

Important: read before using this information

This page is general educational information about a standard industry code set. It is not medical billing, coding, legal, reimbursement, or compliance advice, and it does not create a professional or advisory relationship with ClaimsRevenue.

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