CARC 4CO · Contractual Obligation
The modifier attached to this procedure code doesn't make sense for that procedure, or a modifier required for the code was left off.
- Common causes
- A modifier was appended that isn't valid for the specific CPT/HCPCS code billed, or a required modifier (such as one indicating a distinct service) is missing.
- Suggested fix
- Review the code/modifier combination against current coding guidelines, correct the modifier, and resubmit the corrected claim.
Related Contractual Obligation codes
107This claim depends on another related claim or service being referenced, but that link wasn't provided.11The diagnosis code doesn't support medical necessity for the procedure billed, based on the payer's coverage edits.13The claim shows a date of service after the patient's recorded date of death.146The diagnosis code billed wasn't a valid, active code as of the date of service.150The documentation submitted doesn't justify the complexity or level of the service billed, commonly seen with evaluation and management visit levels.16The claim is missing required information or contains a billing error that prevented the payer from processing it.170This payer doesn't reimburse this specific provider type for this service.171This payer doesn't cover this service when it's billed by this provider type in this particular facility setting.
Frequently asked questions
What does CARC 4 mean?
The modifier attached to this procedure code doesn't make sense for that procedure, or a modifier required for the code was left off.
How do I resolve CARC 4?
Review the code/modifier combination against current coding guidelines, correct the modifier, and resubmit the corrected claim.
Why does CARC 4 happen?
A modifier was appended that isn't valid for the specific CPT/HCPCS code billed, or a required modifier (such as one indicating a distinct service) is missing.
CARC codes maintained by X12 (x12.org). Descriptions on this site are original reference interpretations. Always verify codes with authoritative sources before making billing decisions.