MA04 Denial Code: Secondary claim is missing the primary payer's details
The secondary payer cannot price this claim because the primary payer's identity or payment details were missing, incomplete, or unreadable. Resubmit with full primary EOB information.
- Group code
- N/A (no group code)
- Code type
- RARC
- Billable to patient?
- No - fix the paperwork and resubmit; do not bill the patient for a coordination gap
- Appealable?
- No - resubmit with primary EOB
- Category
- Coordination of Benefits
LQ*HE*MA04Appears as a remark code alongside a claim adjustment reason code.What MA04 means
MA04 is a remark code that rides along with a claim-level adjustment - most often CARC 22 - when a secondary payer receives a claim without usable information about the primary. Before a secondary plan can calculate its share, it has to see who the primary payer is and what that payer paid, allowed, and adjusted. If those details are missing from the electronic COB segments, or a paper EOB is partial or illegible, the secondary claim stops cold. In Medicare Secondary Payer situations it also surfaces when Medicare's MSP records disagree with how the claim was billed. The fix is administrative - supply the primary adjudication data and resubmit - not an appeal.
Common causes
- The primary payer's payment, allowed, and adjustment amounts were never populated in the claim's COB loops.
- A paper claim went out with a partial or illegible primary EOB attached.
- The primary payer's identity was missing from the claim entirely.
- The claim was billed to the secondary before the primary finished adjudicating.
- Medicare's MSP records do not match the payer order the claim was billed under.
- Primary adjudication data was keyed incorrectly into the billing system.
How to fix it
- Obtain the primary payer's finalized remittance or EOB for the exact dates of service.
- Resubmit the secondary claim with complete primary payment, allowed, and adjustment amounts in the COB segments - or a clean, legible EOB copy on paper.
- Verify the payer order is correct before rebilling; if the payer you billed is actually primary, fix the order instead.
- For Medicare Secondary Payer issues, confirm or update the MSP record through the Benefits Coordination & Recovery Center before resubmitting.
- If the primary has not adjudicated yet, hold the secondary claim until the primary remit posts.
How to prevent it
- Verify all active coverages and payer order at every visit, not just annually.
- Do not release secondary claims until the primary remittance has posted.
- Confirm your billing software maps primary adjudication data into the secondary 837 COB segments correctly.
- Audit which payers cross over automatically versus which need direct secondary billing, so claims are not sent down the wrong path.