Claim adjustment reason code
Denial code CO-20 meaning
CARC 20, usually seen as CO-20: The payer sees this injury or illness as covered by a liability insurer.
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- Reason code
- CARC 20
- Short name
- Liability carrier should pay
- Plain meaning
- The payer sees this injury or illness as covered by a liability insurer.
- Group codes
- CO-20: Contractual obligation. The provider absorbs the amount under its contract or the payer's rules. Do not bill the patient for it.
Plain-English summary written by Rivvi. X12 owns the CARC list and its exact wording, which is not reproduced here. Read it on the X12 CARC list (list dated November 1, 2025, checked October 23, 2026). This page does not decide how a claim is paid.
Common causes
- The claim shows an accident another party may be liable for.
What to check before resubmitting
- Get the liability carrier's information from the patient and bill it.
- Correct the accident fields if they are wrong.
Related reason codes
Related pages
Questions
What does denial code CO-20 mean?
The payer sees this injury or illness as covered by a liability insurer. This is Rivvi's plain-English summary of CARC 20. X12's exact wording is on x12.org.
How do I fix CO-20?
Get the liability carrier's information from the patient and bill it. Correct the accident fields if they are wrong.
Can I bill the patient for CO-20?
With group code CO, no. CO means the provider absorbs the amount under its contract or the payer's rules.
Which group codes come with CARC 20?
Most often CO (contractual obligation). The group code, not the reason code, says who owes the amount.
What is the difference between a CARC and a RARC?
A claim adjustment reason code (CARC) says why a claim line was paid differently than billed. A remittance advice remark code (RARC) adds detail, such as which field is missing.