MA04 remark code

Remittance advice remark code MA04. Remark codes add detail to the reason code on the same claim line.

Primary payer information needed

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 MA04 means

The payer cannot process this as a secondary claim without the primary payer's identity or payment details.

The payer believes it is secondary for this patient and needs to know who paid first and what that payer did. The claim did not include that information, or it was incomplete.

It usually comes with reason code 16 or 22. Send the claim again with the primary payer's details and adjudication information, usually at line level.

Common causes

• The primary payer's name, ID or payment amounts were left off a secondary claim.
• The claim was sent to the secondary payer before the primary had processed it.
• The payer's file shows other coverage that the claim did not report.

What to do next

1. Confirm the order of coverage with the patient and both payers.
2. Add the primary payer's information and remittance amounts to the claim.
3. Resubmit the secondary claim, or attach the primary remittance if the payer requires paper.

Related codes

• 22 (reason code) Another payer may be primary
• MA64 (remark code) Third payer needs both prior payments
• MA92 (remark code) Other insurance plan details missing
• M56 (remark code) Missing or invalid payer identifier