Coordination of Benefits

Modified on Wed, 12 Nov at 10:30 AM

★ Overview : Many providers ask how secondary billing works. This article explains what’s supported, what’s not, and what to do in each scenario.

► Audience : Billers & Office Managers

■ Article type: Conceptual topics

❓How Primary & Secondary Insurance Works

When a patient has two insurance plans—such as an employer-sponsored plan and coverage through a spouse's plan—the billing process follows a specific sequence.

For a $200 office visit, the primary insurance processes the claim first. They might allow $160 based on their contracted rate, leaving a $40 patient responsibility (such as a copay or coinsurance).

The claim then moves to the secondary insurance, which reviews what the primary plan already processed. The secondary may cover all or part of that remaining $40 patient responsibility, depending on their plan rules and any coordination of benefits provisions.

The key is that the secondary insurance never pays until the primary insurance has finished processing their portion—whether that results in a payment or a denial.

☁ Importance of an Eligibility Check

Before submitting a claim to Zaya, it’s essential to verify the patient’s insurance eligibility for both primary and secondary coverage. Running an eligibility check confirms which payer is primary and helps identify coordination of benefits (COB) issues early. Incorrect COB setup can lead to denials or claim delays. See our article which plans Zaya covers for a full list.

⚠️ Remember: secondary payment is not guaranteed. Each payer independently reviews and applies their own coverage rules.

❓How does Zaya Handle COB and Secondary Billing?

➡️ We currently do not support secondary billing within our system.

If the patient has secondary insurance that is not in network with Zaya, you’ll need to handle both steps directly:

✔️ Submit the primary claim through your own system and Tax ID.

✔️ Once the primary claim posts, submit the secondary claim through your own billing system.

Secondary claims must always be submitted by the same billing entity (same Tax ID and NPI) that filed the primary claim.

Table 1: Before Claim Submission

Scenario	Primary Insurance	Secondary Insurance	Can Zaya Accept the Claim?	Notes / Required Action
Patient has only one active primary insurance within Zaya network	✅ In-network	❌ None	✅ Yes	Proceed with standard claim submission.
Patient has primary and secondary insurance, both in Zaya network	✅ In-network	✅ In-network	⚠️ Partial	Zaya can process the primary claim only. Secondary billing is not supported.
Patient has primary insurance outside Zaya network and secondary within	❌ Out-of-Network	✅ In-network	❌ No	Zaya cannot accept because primary must be billed first.
Patient has secondary-only coverage (no active primary on file)	❌ None	✅ In-network	❌ No	Zaya cannot submit secondary-only claims.
Patient has missing or unclear COB information	⚠️ Unknown	⚠️ Unknown	⚠️ Hold	Verify insurance hierarchy (primary vs. secondary) before submission.

Table 2: After Claim Submission (COB or Denial Scenarios)

Scenario	Denial Reason / Status	Can Zaya Resubmit or Bill Secondary?	Notes
Claim denies for COB and patient has another primary within Zaya network	COB / Other primary not billed	✅ Yes, resubmit with correct primary info	Zaya will not bill the secondary.
Claim denies for COB and patient's primary is outside Zaya network	COB / Out-of-network primary	❌ No	Zaya cannot process out-of-network primaries; patient or external biller must handle.
Claim processed by primary, and patient has secondary coverage	Primary EOB received	❌ No	Zaya will not submit to secondary. The patient can submit a member reimbursement to secondary plan