CO-5 denial code
Procedure code or type of bill inconsistent with the place of service
How to fix it
Confirm where the service was actually delivered, correct the place-of-service code and resubmit.
How to prevent it
Default the place of service per location and per provider schedule rather than letting it be keyed per claim.
In practice
An inpatient consultation is billed with place of service 11 because the claim was built from an office template. The payer returns CO-5, since the code reported is not payable in an office setting.
This edit compares two fields that must agree: the procedure code and the setting in box 24B. Many codes are valid in one setting and not another, and the fee schedule carries separate values for facility and non-facility work precisely because the resources differ.
Once the setting is corrected to the hospital value and the claim resubmitted, it adjudicates normally. Worth noting is that the corrected claim will pay the facility rate, which is lower — the original higher expectation was itself the artefact of the error.
What sits behind it
The distinction from CO-58 is subtle but real. CO-5 says the code cannot be reported in the setting given; CO-58 says the payer considers the treatment inappropriate for that setting. The first is nearly always a claim build problem and the second sometimes involves a coverage judgement.
Codes carrying an inherent setting are the usual sources: inpatient and observation care, emergency department services, nursing facility visits, and home visit codes. Each was written for one location, so pairing any of them with a mismatched place of service is a straightforward contradiction the payer can detect automatically.
The durable fix is configuration rather than vigilance. Setting the place of service by scheduling location and provider rather than by claim entry removes the opportunity for the error, and practices that do this stop seeing the code entirely rather than seeing less of it.
Related codes
Terms used here — CMS-1500 · CPT Code · Claim Scrubbing
How we handle it — Medical Coding · Claims Management · Revenue Cycle Management
Primary sources
The rules behind CO-5, at the bodies that publish them.
- CPT code set (opens in a new tab)
American Medical Association — Maintainer of CPT. Annual changes to CPT are the most common cause of a sudden, unexplained rise in denials each January.
- Claim Adjustment Reason Codes (CARC) (opens in a new tab)
X12 — The authoritative, maintained CARC list. Our denial code lookup explains these in plain English; X12 is where the canonical definitions live.
- National Correct Coding Initiative (NCCI) edits (opens in a new tab)
Centers for Medicare & Medicaid Services — The procedure-to-procedure and medically-unlikely edits behind most bundling denials. Checking these before submission prevents the denial entirely.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-5
The one describing where the patient physically was when the service was furnished, not where the provider was or where the practice is registered. Office is 11, patient home is 12, inpatient hospital is 21, on-campus outpatient is 22, off-campus outpatient is 19, and telehealth splits between 10 for home and 02 for elsewhere.
Because the fee schedule carries two practice expense values for most codes. The non-facility rate assumes the practice supplied the room, staff and equipment. The facility rate applies where a hospital supplied them and bills separately, so the professional payment is lower by design.
Yes, and it is one of the more reliable edits to build. A table pairing each procedure code with the settings in which it is payable will catch the mismatch before submission, and pre-filling the setting from the scheduling location removes most of the errors before the scrubber ever sees them.
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