MA63 remark code

Remittance advice remark code MA63. Remark codes add detail to the reason code on the same claim line.

Missing or invalid principal diagnosis

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What MA63 means

The principal diagnosis code on the claim is missing, incomplete or not valid.

The payer could not use the principal or first listed diagnosis. It may be blank, not coded to full specificity, invalid for the date, or a code not allowed in the principal position.

It usually comes with reason code 16, and the claim is returned for correction.

Common causes

• The principal diagnosis was left blank.
• A code that cannot be used as a principal diagnosis was put first.
• The code was not valid or not complete for the date of service.

What to do next

1. Ask coding to review the principal diagnosis against the record.
2. Check the code's validity and length for the date of service.
3. Send a corrected claim with a valid principal diagnosis listed first.

Related codes

• 16 (reason code) Missing information or billing error
• M76 (remark code) Missing or invalid diagnosis code
• M81 (remark code) Code to the highest level of detail