Medicare Crossover Claim: Why Your Secondary Payer Is Not Paying
Direct answer: A Medicare crossover claim is a claim that Medicare automatically forwards to a patient's secondary payer, usually a Medigap or supplemental plan, after Medicare processes it. The forwarding happens through the Coordination of Benefits Agreement (COBA) program, and it exists so the provider does not have to file the same claim twice. When the secondary payer is not paying, the usual causes are that the crossover never happened, that the secondary payer received it but rejected or denied it, or that the secondary payer paid but the payment was never posted. Each cause lives in a different place, so the first job is to find where the claim stopped, not to rebill it blindly.
How crossover is supposed to work
After Medicare adjudicates a claim, and where a COBA arrangement covers that secondary payer, Medicare sends the claim information on to the secondary payer automatically. The secondary payer then processes its share, such as coinsurance or deductible amounts that Medicare did not pay, and sends its own remittance. The provider's job is to confirm the crossover happened, watch for the secondary remittance, and post it. When everything works, nobody files a second claim. When it does not, the balance ages in A/R, and because the claim looks "already sent," it is easy for nobody to chase it.
Where it stops, and how to tell
There are three stopping points. First, Medicare never forwarded the claim. Signs: the Medicare remittance shows no crossover indicator, or the secondary payer has no record of receiving it. Common reasons include the secondary payer not participating in COBA for that plan, missing or incorrect secondary payer information on the claim, or the claim being one of the types Medicare does not cross over. Second, the secondary payer received it but did not pay. Signs: the secondary payer can see the claim but shows a rejection, a denial, or a pending status. The reason may be a secondary-plan rule, a timely filing issue, or missing information the secondary payer needs. Third, the secondary payer paid but the payment was never posted. Signs: the secondary payer shows a payment, but your system shows the balance open. That is a posting problem, not a payer problem, and rebilling will only create a duplicate.
What to do, step by step
First, check the Medicare remittance for the crossover indicator and any message about forwarding. Second, call or check the portal of the secondary payer and ask whether it received the claim, and if so, in what status. Third, if Medicare never forwarded it, file the claim directly to the secondary payer with the Medicare remittance attached, and check the secondary payer's timely filing limit before you do, because that clock may already be running. Fourth, if the secondary payer rejected or denied it, work that rejection or denial on its own terms, with the secondary payer's reason codes, not Medicare's. Fifth, if the secondary payer paid, find and post the payment, and reconcile the remaining balance. Sixth, record where the claim stopped, so the same payer pair does not stall the same way next month.
Worked example
A claim for a Medicare patient with a Medigap plan shows a $180 coinsurance balance open for 60 days. The Medicare remittance shows no crossover indicator. The secondary payer's portal shows no record of the claim. The biller files the claim directly to the secondary payer with the Medicare remittance, and the secondary payer pays the coinsurance. The root cause was a crossover that never happened, and the fix was a direct filing, not a rebill to Medicare. Had the biller rebilled Medicare instead, the claim would have denied as a duplicate and the balance would have aged further.
Timely filing is the hidden risk
Crossover failures are dangerous because they are silent. While the balance sits waiting for a secondary payment that is never coming, the secondary payer's timely filing deadline keeps running. By the time someone notices, the window may have closed. Build a simple control: any Medicare claim with a secondary payer and an open balance past your normal secondary-payment window gets checked for crossover status, every week, without exception. That one report prevents most crossover write-offs.
When the secondary payer is not a COBA participant
Not every secondary payer receives crossover claims. Some supplemental plans, employer plans, and other secondary coverages are not part of COBA for a given patient, and some claim types are excluded. In those cases, filing directly to the secondary payer with the primary remittance is the normal route, not a workaround. Confirm the secondary payer's filing rules and timely filing limit at intake, so the direct filing happens promptly instead of after a month of waiting for a crossover that will never come.
Medicare crossover checklist
- Medicare remittance checked for the crossover indicator.
- Secondary payer contacted: received, rejected, denied, paid, or never received.
- Correct next step chosen: direct filing, secondary denial work, or payment posting.
- Timely filing limit for the secondary payer checked before any filing.
- Payment posted and balance reconciled when paid.
- Stopping point recorded, and the payer pair flagged if the same failure repeats.
Frequently asked questions
What is a Medicare crossover claim? A claim Medicare forwards automatically to a secondary payer through the COBA program after Medicare processes it.
Why would a secondary payer not receive it? The plan may not participate in COBA for that patient, the secondary payer information on the claim may be missing or wrong, or the claim type may be excluded from crossover.
Should I rebill Medicare if the secondary payer has not paid? No, not until you know where the claim stopped. If Medicare already processed it, rebilling Medicare risks a duplicate denial.
What do I send when filing directly to the secondary payer? The claim plus the Medicare remittance showing what Medicare paid and what remains, following the secondary payer's own filing instructions.
How long should I wait for a secondary payment? Do not wait on assumption. If no secondary remittance arrives within your normal secondary-payment window, check crossover status that week, because the secondary timely filing clock is running.
What if the secondary payer paid but my system still shows a balance? That is a posting problem. Find the secondary remittance, post it, and reconcile before doing anything else.
A note on programs and rules: COBA and Medicare secondary-payer rules are summarised in general terms. Always confirm a payer's participation, filing rules, and timely filing limits against that payer's own guidance before acting. This article is educational information about billing workflows, not legal or compliance advice.
Need help clearing stalled crossover balances before timely filing runs out? Neximed Billing provides A/R follow-up, secondary billing, and payment posting. Contact us at info@neximedbilling.com or +1-406-2251570.