Medicare Crossover Claims: Step-by-Step Guide for Providers

Medicare crossover claims play a critical role in ensuring providers are reimbursed accurately and efficiently when patients have both Medicare and secondary insurance. In a landscape where billing errors can easily disrupt revenue cycles, understanding how crossover claims function is essential. For providers, including those offering ABA billing services, understanding how to manage these claims is critical for smoother reimbursement and compliance. This guide provides a step-by-step walkthrough, clarifies the crossover claim definition, and explains why clean processes matter for providers.

What Are Medicare Crossover Claims

A Medicare crossover claim is a claim that Medicare automatically forwards to a patient’s secondary insurer after processing its portion of the payment. Instead of requiring providers to bill the secondary payer separately, Medicare does the forwarding through its Coordination of Benefits Agreement (COBA).

This setup is particularly helpful for:

• Dual-eligible patients with both Medicare and Medicaid.

• Patients with Medigap policies that cover deductibles or coinsurance.

• Commercial secondary insurance tied to employer or private plans.

The purpose of crossover claims is simple: reduce administrative work for providers, minimize billing errors, and ensure patients are not charged for balances that their secondary plan should cover. Without crossover, billing staff often need to resubmit claims manually, post secondary payments themselves, and chase balances that too easily slip through the cracks.

How Medicare crossover claims work: the five-stage flow

Think of the Medicare crossover process as a five-step relay, where clean execution at each handoff ensures full reimbursement.

Stage 1: Set the Table

Start with verifying Medicare eligibility and confirming whether the secondary payer is COBA-linked to Medicare. Cross-check patient demographics—name, DOB, gender, and address must align across systems. Complete and store the MSP questionnaire—missteps here are the top reason crossovers fail. For Medicaid, verify eligibility month by month; for Medigap or commercial, capture the exact policy and group ID.

Stage 2: Submit a Clean Medicare Claim

Bill Medicare first using the appropriate form (837P/837I or CMS-1500/UB-04). Use accurate NPIs, taxonomy, POS codes, modifiers, and diagnoses. Avoid errors—bad data blocks everything. Some MACs may require you to list the secondary payer; follow local MAC guidance.

Read more about how to improve Medicare claim success and reduce denials here

Stage 3: Medicare Adjudicates

Medicare processes the claim and issues an ERA (835). If the patient has a COBA-linked secondary, a crossover record is generated and passed along.

Stage 4: Secondary Payer

The secondary payer receives the Medicare decision, applies its rules, and pays or denies its share. You’ll get a second ERA to post and close the claim.

Stage 5: Payment Finalized

Once both payments are in, write off contractuals or small balances as needed. If done right, the crossover process is seamless—no resubmissions required.

Checklist of Documents Needed to Submit a Crossover Claim

Even though many crossover claims happen automatically, providers must ensure proper documentation is in place. Here’s your must-have checklist:

• Patient’s Medicare card (with correct MBI number)

• Secondary payer information (including payer ID and eligibility)

• Signed CMS-1500 or UB-04 form with appropriate diagnosis and CPT codes

• Authorization documents, if needed

• COB verification records (sometimes Medicaid requires recent updates)

Having these on file ensures a crossover claim flows without interruption, especially when issues arise or manual resubmission becomes necessary. Learn more about safeguarding your documentation and compliance.

Entering Medicare Crossover Details Correctly in the UB-04 Claim Form

Billing errors often start on the UB-04 form. When entering crossover claims, follow these details precisely:

• Box 50: List Medicare as the first payer (Line A), Medicaid or secondary as Line B or C.

• Box 58-62: Include the patient’s name, payer ID, and policy number for each listed payer.

• Box 67: Enter ICD-10 diagnosis codes (primary and secondary).

• Box 80: Note Crossover Claim if manually submitting, to avoid payer confusion.

Correct formatting ensures the claim is processed accurately, whether automatic or manual submission occurs.

Key Remittance Codes That Confirm Medicare Crossover Success

After you submit a claim, the RA holds the key to confirming whether the Medicare crossover worked.

Watch for these codes:

• MA18: Claim automatically forwarded to the secondary payer.

• MA07: Missing or incorrect secondary payer information.

• N89: Payer not set up to receive crossover claims.

• CO-22: Coverage/eligibility issues—manual action needed.

If you see MA18, you’re good. If not, follow up with the secondary payer or correct COB files with CMS.

Troubleshooting Steps When a Crossover Claim Is Denied

Even if a crossover claim is automatically sent, things can go wrong. Here’s what to do if your crossover claim is denied:

• Check the Remittance Advice:  Look for denial codes like CO-22, MA07, or N89. These often mean Medicare tried to forward the claim, but couldn’t.

• Validate Coordination of Benefits: Log into the CMS portal or contact your MAC to verify the patient’s COB file. Update if needed.

• Manually Submit the Claim: Send the UB-04 or CMS-1500 to the secondary payer with Medicare’s RA attached.

• Contact the Secondary Payer: Call or submit an electronic inquiry if the claim has been pending for over 30 days without payment.

• Update Patient Files: Always update COB details in your EHR or billing software to avoid future denials.

Manual submission isn’t ideal, but it’s the only path if automatic crossover fails.

Understanding Timelines and Payment Windows for Medicare Crossover Claims

Medicare usually processes claims within 14-30 days. Once processed:

• The secondary payer should receive the crossover claim automatically within 7–10 days.

• Payment from the secondary is typically received within 15–30 days after they receive it.

Key Points on Timelines

• Dual-eligible beneficiaries (Medicare + Medicaid) should receive seamless crossover.

• If you haven’t received a secondary payment within 45 days, start manual follow-up.

• Timely filing limits vary: Medicaid may allow 90 days from the Medicare RA date; commercial insurers often allow 180 days.

Delays in Medicare crossover often point to COB mismatches or incorrect billing entries.

Want help making your crossover processes audit‑ready? Read about avoiding OIG audits in billing compliance

FAQ

1. How do providers submit claims to Medicare?

Providers send claims electronically using HIPAA‑standard formats like 837P/837I or on paper with CMS‑1500 or UB‑04 forms, making sure coding, eligibility, and documentation are accurate.

2. Who processes Medicare claims?

Medicare Administrative Contractors (MACs) handle claims for the Centers for Medicare & Medicaid Services, reviewing submissions, applying coverage rules, and issuing payments or remittance advice to participating healthcare providers.

3. How to submit for reimbursement through Medicare?

File electronically via your clearinghouse or directly through your MAC’s portal using approved claim formats. Include complete patient, provider, and service details to meet Medicare’s requirements for timely reimbursement.

Conclusion

Crossover claims improve billing efficiency—but only when done right. By understanding what Medicare crossover is, how it works, and what documentation matters, providers can eliminate payment delays and clean up their revenue cycle.

Medicare’s system is built to work for you, but it’s not hands-free. Proactively tracking remittances, verifying COB records, and correcting errors is the key to getting fully paid.