Remark Code M77 on Your EOB — Meaning & What to Do

Remittance Advice Remark Code (RARC)

What remark code M77 means: The place of service is missing, incomplete, or invalid.
What to do about remark code M77: Ask the provider's billing office to explain or correct this, and resubmit if needed.

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 M77.

Seeing remark code M77 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 M51The procedure code is missing, incomplete, or invalid. RARC M79The charge amount is missing, incomplete, or invalid. RARC M39This service isn't covered because it's considered routine. RARC M80This service can't be paid on the same day as a related service.

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Frequently asked questions about Remark code M77

What does remark code M77 mean on my EOB?

The place of service is missing, incomplete, or invalid.

What should I do about remark code M77?

Ask the provider's billing office to explain or correct this, and resubmit if needed.

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.