MA04MA-series (Medicare alerts & claim-level)COB & Secondary
MA04: Secondary claim needs primary payer info
The payer can't process as secondary because the primary payer's identity or payment details weren't included or were unreadable.
Commonly appears with these denial codes
The denial code gives the category; MA04 pinpoints the specific problem. Read them together before touching the claim.
What to do about it
Rebill with the primary's EOB/ERA data attached or keyed into the COB fields (paid amount, adjustments, patient responsibility). Electronic COB segments beat paper attachments.
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