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CO-48 Denial Code (Deactivated): Procedure Not Covered

CO-48 meant the procedure billed was not a covered benefit. X12 deactivated it, and its notes tell payers to use CARC 96 instead, together with a remark code giving the specific reason.

X12 deactivated CARC48 on October 16, 2003. Payers should no longer use it on new remittances, but it can still appear on older ERAs, corrected claims, and appeals.

Quick facts

Code
CO-48 (CARC 48)
Status
Deactivated StoppedOctober 16, 2003 (in use since January 1, 1995).
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider wrote off the procedure, usually because no valid patient waiver was on file.
  • PR (Patient Responsibility): The patient could be responsible when the plan excluded the procedure and the patient agreed to pay.
Official description
This (these) procedure(s) is (are) not covered.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-48 meant

CARC 48 told the provider the payer would not pay for the procedure itself. Unlike a denial for missing paperwork or bad coding, the message was that the procedure fell outside the benefits the plan offered, at least as the payer read the claim.

What replaced it

The official note reads “Use code 96,” making CO-96 the replacement. Code 96 requires a remark code so the provider knows which exclusion or limit applied.

Depending on the reason, payers may also use more specific codes: CO-55 for experimental procedures, CO-49 for routine or screening services, or PR-204 for services outside the current plan.

If you still see CO-48

Treat it as historical. If a claim was reprocessed or appealed long after the fact, the new remittance should carry an active code such as 96.

For the claim itself, verify the procedure code billed matches the documentation and look up the plan’s coverage policy for that procedure. If a valid financial waiver was signed before the service, the patient can typically be billed. If not, and there is no basis for an appeal, post the amount as a write-off and consider a benefits check for similar procedures in future.

  • CO-96 (Non-covered charge(s).): Named replacement for this code: non-covered charges, with a required remark code.
  • CO-55 (Procedure/treatment/drug is deemed experimental/investigational by the payer.): The procedure is considered experimental or investigational.
  • CO-49 (This is a non-covered service because it is a routine/preventive exam or a diagnostic/screening procedure done in conjunction with a…): Routine or preventive services the plan does not cover.
  • PR-204 (This service/equipment/drug is not covered under the patient's current benefit plan): Not covered under the patient's current benefit plan.

CO-48 FAQ

How is CO-48 different from CO-46?

CO-46 said a service was not covered; CO-48 said a procedure was not covered. X12 retired both and directed payers to CARC 96 for either case.

Should I appeal a procedure-not-covered denial?

Only if you have reason to think the procedure is covered, for example under a policy exception or because the plan's coverage policy supports it for the patient's diagnosis. A true plan exclusion usually cannot be overturned.