Picture this for a moment, your billing team has closed out the day, primary claims are moving, and the aging report looks reasonable. Then someone digs into unpaid balances and finds a quiet backlog of claims that should have gone to secondary payers and never did. Nothing dramatic, just a slow drip of missed revenue and extra patient statements.
That is the story behind secondary billing workflows. They do not usually fail loudly, but when they are weak, they hurt access, throughput, and staff workload all at once. In a system where administrative expenses can account for roughly 15 to 25 percent of total national health care spending, with billing and insurance related work as a major driver, even modest improvements in these workflows matter for the bottom line and for patient experience, see research published in JAMA on administrative expenses in US health care.
At the same time, many clinics are modernizing their front office. Platforms such as Solum Health position an AI powered front office as an AI powered unified inbox and AI intake automation layer for outpatient facilities, specialty ready and integrated with EHR and practice management systems, built to deliver measurable time savings. Secondary billing sits right next to that layer. It depends on clean data, consistent routing, and a clear handoff between people and systems.
A secondary billing workflow is the structured process your organization follows once the primary payer has finished reviewing a claim. The primary plan pays what it owes under its contract. Anything left over that might be covered by a second plan moves into this secondary flow.
In practice, that means staff review the explanation of benefits from the primary payer, apply coordination of benefits rules, then decide whether a secondary insurer should be billed, and how. Coordination of benefits rules, including when an employer plan, Medicare, or another payer is primary, are spelled out in federal guidance from the Centers for Medicare and Medicaid Services, see the Coordination of Benefits overview on the CMS site.
A good secondary billing workflow does three things at once. It protects revenue, it keeps patients from being billed before all insurance options are exhausted, and it limits rework for your billing team.
You can think of the process as a series of checkpoints. The details vary by payer, but the underlying logic is consistent.
The starting point is the primary explanation of benefits. It tells you what was paid, what was adjusted, what was denied, and what has been assigned to patient responsibility. Without this document, there is no legitimate path to secondary billing.
Someone has to read that explanation carefully. Adjustment codes, contractual write offs, and denial reasons can look cryptic, and misreading them is an easy way to send claims to the wrong place. At this stage you are asking a simple question, is there a remaining balance that a secondary payer is meant to consider.
Next comes coordination of benefits. Staff confirm the order of payers, check that the secondary coverage was active on the date of service, and confirm that the service type is covered under that plan. Errors here show up later as secondary denials, possibly after deadlines have passed.
Once you know that a secondary claim is appropriate, you build it from the primary outcome. That means pulling in paid amounts, adjustment codes, and remaining balances, then formatting the claim according to the secondary payer’s rules. Some payers expect the primary explanation to be attached. Others rely on electronic data passed through clearinghouses.
Submission is where timing becomes critical. Filing limits for secondary claims are often tighter than for primary claims, and they are easy to overlook in a busy office. In my view, this is where checklists and clear ownership make the difference between a manageable workflow and a constant scramble.
After submission, the claim enters a period that looks like waiting but should be active tracking. Requests for documentation, partial payments, or denials need quick attention. If your team already uses a unified inbox for patient messages, you can apply the same logic here, one queue, clear routing, visible status.
When the secondary payer finishes processing, you post payments and adjustments, then decide what to do with any remaining balance. That may involve a patient statement, a contractual write off, or an internal policy review if patterns appear. This last step is easy to treat as housekeeping, but it is where you see whether the workflow is truly closing the loop.
If you are reading this as a practice administrator, you can tighten secondary billing without a major system overhaul. The key is to define a small scope and give it real structure.
Start with one high volume payer combination and one service line. For example, you might focus on patients who have a commercial plan as primary and a public program as secondary. Map the existing steps on paper, including who touches the claim and where information lives.
Second, standardize the review of primary explanations. A simple checklist that covers key items, paid amount, adjustment reason codes, remaining balance, and secondary eligibility, can cut down on interpretation errors. This is also a good place to embed checks that support patient language preference capture and preferred communication channel capture, so follow up outreach is more likely to reach the right person through the right channel.
Third, move tracking out of individual inboxes and into a shared queue. If your front office is already running an AI powered unified inbox, or exploring patient reminder automation, secondary claims that are waiting on action can follow the same workflow, one place where staff see what needs attention today.
Fourth, write a short playbook for exceptions. For example, how the team should respond when a secondary payer requests more documentation, when payer order looks wrong, or when the claim is approaching its filing limit. People do better when they are not inventing a process from scratch every time.
Most problems in secondary billing show up in familiar patterns. If you recognize these, you are not alone.
One pitfall is delayed posting of primary outcomes. When primary explanations sit unposted, secondary deadlines pass quietly in the background. Another is partial or outdated insurance information, especially for patients whose coverage changes midyear.
Manual tracking is a third weak spot. Spreadsheets, notebooks, and memory based follow up rarely hold up under staff turnover or volume spikes. In contrast, blending an operational view of time and workload with centralized queues tends to make bottlenecks visible earlier.
A fourth pitfall is treating secondary billing as a low priority task. It may not feel as urgent as same day authorizations or appointment scheduling, but it represents real money and real trust with patients.
Finally, the broader context matters. Analyses of US health spending, including work published by Health Affairs, estimate that administrative complexity accounts for roughly 15 to 30 percent of total costs, with billing and insurance related work as a major component. If you feel as though you are fighting an uphill battle here, that perception has data behind it.
What is the difference between primary and secondary billing
Primary billing goes to the insurer that is expected to pay first under coordination of benefits rules. Secondary billing only begins after that primary claim has been processed, and it applies to remaining balances that the secondary plan is responsible for.
When should a secondary claim be submitted
Ideally, you submit a secondary claim as soon as the primary explanation of benefits is available and coordination of benefits has been confirmed. Waiting longer than necessary raises the risk that filing limits will be missed or that staff will lose track of which claims are still pending.
Do all patients have secondary insurance
No, many patients have only a single active insurance plan. Secondary billing workflows apply only when a patient has more than one plan in place for the service in question, for example an employer plan and a supplemental policy.
Why are secondary claims denied so frequently
Most denials trace back to a handful of causes, incorrect payer order, inactive coverage on the date of service, missing or unreadable primary explanation of benefits information, or services that the secondary policy does not cover. A consistent checklist at the start of the workflow usually reduces these issues.
How can clinics reduce errors in secondary billing
The most reliable approach is to standardize the steps and reduce the number of places where information can be lost. Clear ownership, shared queues, and simple rules about when to reach out to the patient or payer, supported by tools such as message read receipts and preferred communication channel capture, give staff a more predictable, less stressful workload.
If you want to improve secondary billing this month, not next year, pick one segment of your payer mix and run a focused pilot. Map the current workflow, write a one page checklist, and move tracking into a single queue that your team can see and act on. Where it fits, connect that queue to an AI powered unified inbox and AI intake automation layer so that information flows in both directions.
From there, review a small sample of secondary claims at the end of each week. Look at turnaround time, denial reasons, and staff effort. Adjust the checklist, refine responsibilities, and carry forward what works. In a landscape where administrative burden keeps climbing, a clear secondary billing workflow is one of the cleaner wins available to outpatient leaders.
