Remark Code MA18 on Your EOB — Meaning & What to Do

Remittance Advice Remark Code (RARC)

What remark code MA18 means: This claim was also forwarded to your secondary insurer.
What to do about remark code MA18: Wait for the secondary insurer's statement before paying.

Remark codes add detail to a claim decision. They appear alongside the main adjustment codes on your Explanation of Benefits or remittance notice, giving the specific reason behind remark code MA18.

Seeing remark code MA18 on your EOB?
A denial code tells you what the payer reported, but it may not tell the whole story. Reviewing your EOB and bill together can help clarify what may need attention.

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Related codes

RARC MA15Your claim was split for processing. RARC MA27Your Medicare ID number is missing, incomplete, or invalid. RARC MA13You may be responsible for a portion under a specific program rule. RARC MA130The claim has a missing or invalid field and can't be processed as is.

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Frequently asked questions about Remark code MA18

What does remark code MA18 mean on my EOB?

This claim was also forwarded to your secondary insurer.

What should I do about remark code MA18?

Wait for the secondary insurer's statement before paying.

Seeing this code on your own EOB?
Upload the EOB, the bill, or both — MD Bill Check reads the codes on your documents, compares them side by side, and flags what's worth questioning. Free, no account needed.

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Last reviewed 2026-07-07 · MDBillCheck Editorial Team. Plain-English explanations are original wording; always verify the specific reason with your insurer.