Remittance advice remark code
Remark code M51 meaning
RARC M51: A procedure code on the claim is missing, incomplete or invalid.
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- Remark code
- RARC M51
- Short name
- Procedure code missing or invalid
- Plain meaning
- A procedure code on the claim is missing, incomplete or invalid.
- Kind
- Adds detail to the reason code on the same line.
Plain-English summary written by Rivvi. X12 owns the RARC list and its exact wording, which is not reproduced here. Read it on the X12 RARC list (list dated July 1, 2026, checked October 23, 2026). This page does not decide how a claim is paid.
What to check before resubmitting
- Check the code exists for the date of service.
- Check the code and its modifiers were keyed right.
Reason codes it often comes with
Related remark codes
Related pages
Questions
What does remark code M51 mean?
A procedure code on the claim is missing, incomplete or invalid. This is Rivvi's plain-English summary of RARC M51. X12's exact wording is on x12.org.
What should I do about M51?
Check the code exists for the date of service. Check the code and its modifiers were keyed right.
Is M51 a denial?
A remark code adds detail to the reason code on the same line. The reason code (CARC) and its group code decide what was denied or adjusted. It is often paired with reason codes 16, 181.
What is the difference between a RARC and a CARC?
A remittance advice remark code (RARC) adds detail to a claim adjustment reason code (CARC). The CARC says why the line was adjusted. The RARC often says what to fix.