N479 Denial Code: Primary payer's EOB was not included with the claim
The primary payer's Explanation of Benefits never reached the secondary payer, so it cannot coordinate benefits. Resubmit with the primary EOB or complete electronic payment data.
- Group code
- N/A (no group code)
- Code type
- RARC
- Billable to patient?
- No - remark codes carry no dollar amount; patient responsibility follows the paired CARC's group code
- Appealable?
- Fix and resubmit with the EOB
- Category
- Coordination of Benefits
LQ*HE*N479Appears as a remark code alongside a claim adjustment reason code.What N479 means
N479 shows up on secondary or Medicare Secondary Payer claims when the primary payer's EOB - or the equivalent electronic remittance data - did not arrive with the claim. Without it, the second payer cannot see what the primary allowed, paid, and adjusted, so coordination of benefits stalls. As a remark code it rides along with a CARC (often 22, 16, or 252) that carries the actual dollar adjustment, and it is the remark that tells you the fix. That fix is mechanical: obtain the primary remittance, attach it or transmit the primary payment segments correctly, and resubmit. On electronic claims the culprit is frequently incomplete COB loops - the primary's paid amounts and adjustments were dropped in transmission - rather than a literally missing paper EOB.
Common causes
- The secondary claim was submitted before the primary payer finished processing.
- A paper EOB was never attached, or was attached to the wrong claim.
- Electronic COB data - the primary's paid amounts and adjustments - was incomplete or dropped by the clearinghouse.
- The payer has the patient listed as primary when it is actually secondary, so it expects an EOB that does not exist.
- The primary payment posted in the billing system, but the remittance detail was never forwarded onto the secondary claim.
How to fix it
- Pull the primary payer's EOB or 835 and confirm the claim fully adjudicated before resubmitting.
- Resubmit with the EOB attached, or with complete primary payment data in the electronic COB segments.
- If the payer's records have the wrong payer order, correct coordination of benefits with the plan before resubmitting.
- Confirm through the clearinghouse that the primary payment detail actually transmitted - do not assume the system forwarded it.
How to prevent it
- Hold secondary claims until the primary remittance posts, and automate the crossover where payers support it.
- Verify payer order at every eligibility check, not just at intake.
- Audit clearinghouse mapping for COB data so primary payment detail survives the handoff.