When & How to Bill Secondary Insurance for ABA Services?

Billing a second insurance for Applied Behavior Analysis (ABA) services can be tricky, but knowing the right phases makes it much easier. When an individual has two insurance plans, providers are required to follow the Coordination of Benefits (COB) rules to figure out which insurance pays first. The first insurance handles the claim, and then the second insurance may cover what’s left — like deductibles, copays, or coinsurance. 

Getting this right support avoid claim rejections, speeds up payments, and maintains everything compliant. Billing companies like DocVaz Medical Billing are professional at handling these complex claims, helping ABA providers get paid faster so they can concentrate on caring for patients.

Step 1: Figure Out Which Insurance is Primary

First, you need to know which plan pays first. The primary insurance processes the claim before the secondary insurance even looks at it. Here are some common rules to decide:

Birthday Rule:

• If a child is covered under both parents’ plans, the parent with the earlier birthday in the year has the primary plan.

Employment Status: 

• A current job’s insurance usually pays before retiree or COBRA coverage.

Medicaid: 

• Medicaid almost always pays last.

TRICARE: 

• Usually pays after other commercial insurance.

Accident Cases: 

• Workers’ compensation or liability insurance pays first for injury-related claims.

Getting this right matters — secondary insurers will reject claims submitted before the primary insurer has processed them.

Step 2: Send the Claim to the Primary Insurance

Once you understand which plan is primary, submit the ABA claim with the right CPT codes — for example, 97153 for adaptive behavior treatment. The primary insurer understands the claim and decides how much it will permit and pay.

After processing, the insurer sends an Explanation of Benefits (EOB) or Electronic Remittance Advice (ERA), which shows exactly how the claim was handled and gives you the details needed to bill the second insurance.

Step 3: Read the Explanation of Benefits (EOB)

The EOB is very important for billing the second insurance. It tells the secondary payer how much was already paid. Look for these key details:

Allowed Amount: The price the insurer agrees is acceptable for the service.

Paid Amount: How much the primary insurer has already paid.

Adjustment Codes: Codes explaining why some costs weren’t covered.

Patient Responsibility: What the patient owes — deductible, coinsurance, or copay.

For example, if the provider bills $100, the primary insurer allows $85, pays $70, and assigns $15 to the patient’s deductible. The second insurance may then cover some or all of that $15. Companies like DocVaz for Medical Billing Services carefully review EOBs to catch errors that could affect payment.

Step 4: Fix Any Errors Before Billing Secondary

If the primary insurer denies the claim due to mistakes — like wrong codes, missing authorizations, or incomplete information — fix those issues before sending anything to the second insurer. Common reasons for denials include:

• Wrong CPT codes
• Missing authorization
• Incomplete patient details
• Services billed outside coverage guidelines

Only once the primary claim is correctly processed should you move on to the secondary.

Step 5: Send the Claim to the Secondary Insurance

Billing secondary insurance isn’t just about resending the same claim. You need to include information from the primary insurer’s EOB. Required details include:

• Same CPT codes, units, and modifiers
• Primary allowed and paid amounts
• Adjustment codes from the primary payer
• Patient responsibility amounts
• Primary EOB or COB data

Electronic claims include this in COB segments. Paper claims require the “other insurance” section of the CMS-1500 form to be filled out.

Step 6: Understand How the Secondary Payer Calculates Payment

The second insurer looks at what the primary already paid and figures out what it can cover. However, both insurers together can never pay more than the total allowed amount. For example:

• Provider bills $100
• Primary allows $85, pays $70
• Patient owes $15
• Secondary may cover that $15, but some plans use their own fee schedule first.

Billing services like DocVaz Medical Billing know how different payers calculate payments and submit claims accordingly.

Step 7: Track the Claim

Submitting the claim isn’t the end. You need to follow up and make sure it was received and processed correctly. Good habits include:

• Checking claim status every week
• Responding quickly to any payer requests
• Watching the timely filing deadlines
• Following up on slow claims
• Staying on top of claims prevents missed deadlines and payment delays.

Step 8: Post Payments and Update Your Records

Once the second insurer pays, your billing team must record everything accurately in your practice management system. This includes:

• Posting payment to the right claim
• Recording any contractual adjustments
• Identifying remaining patient balances
• Updating financial reports

Outsourcing this to DocVaz Medical Billing helps clinics keep clean financial records and run a smoother revenue cycle.

Step 9: Let the Patient Know

After both insurers have paid, send the patient a clear, easy-to-read statement that explains:

• What did the primary insurance paid
• What the secondary insurance paid
• Any remaining amount the patient owes
• Clear communication reduces confusion and payment disputes.

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