Remittance advice remark code
Remark code MA66 meaning
RARC MA66: The principal procedure code is missing, incomplete or invalid.
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- Remark code
- RARC MA66
- Short name
- Principal procedure missing or invalid
- Plain meaning
- The principal procedure code 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
- Add the principal procedure code to the institutional claim.
Reason codes it often comes with
Related remark codes
Related pages
Questions
What does remark code MA66 mean?
The principal procedure code is missing, incomplete or invalid. This is Rivvi's plain-English summary of RARC MA66. X12's exact wording is on x12.org.
What should I do about MA66?
Add the principal procedure code to the institutional claim.
Is MA66 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 code 16.
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.