Split/Shared Billing in Emergency Medicine: Why Attestation Matters More Than Ever

Emergency departments (ED) are built for urgency. Physicians and non-physician providers (NPP) often work side by side in fast-paced, overlapping workflows delivering timely, critical care. But as team-based care becomes the norm, CMS is taking a closer look at how these shared encounters are billed.

At the center of that scrutiny? Split/shared billing.
The challenge? Documenting it the right way—consistently and in real time.
The opportunity? Protecting compliance and preserving revenue.

Let’s walk through what’s changed, what matters most and how Coronis Health approaches this in the EDs we support nationwide.

In the past, EDs could bill under a physician’s NPI if there was some level of face-to-face interaction with the patient. That allowed for flexibility and especially helpful in the dynamic, high-volume world of emergency care.

But CMS’s 2024 guidance introduced a major shift. Now, the provider who performs the “substantive portion” of the visit must bill the service.

That “substantive portion” can be determined in one of two ways:

• More than 50% of the total time spent with the patient
• Performance of the key components of the medical decision making (MDM)

This dual definition allows EDs some flexibility, but also raises new questions:

• How do we decide who did “most” of the work?
• Do we need to track time precisely?
• How do we document it efficiently without slowing down care?

Time tracking is nearly impossible in a typical ED setting. Providers manage multiple patients, shift between roles and rarely engage in linear, trackable encounters. CMS recognizes this reality, which is why attestation is not just allowed—it’s encouraged.

An effective attestation:

• Clearly identifies the provider who performed the substantive portion
• Specifies the work completed (especially MDM)
• Is documented by the billing provider themselves

Example:

“I, Dr. [Name], have personally performed the substantive portion of this visit, including key components of the medical decision making.”

Without that sentence, coders are forced to make assumptions. Many will default the claim to the NPP, resulting in a 15% reduction in Medicare reimbursement.

That’s revenue leakage—not from missed services, but from missed documentation.

There’s still confusion about what qualifies. To clarify:

• A specific, provider-written statement confirming who led the care? That’s attestation.
• A co-signature on an NPP note? Not enough.
• A general statement like “seen and agree?” Doesn’t meet the requirement.

CMS expects to see clear, active confirmation the billing provider delivered the majority of care whether by time or by decision making. Without that, compliance risks rise—and reimbursement can fall.

For split/shared services billed to Medicare, CMS now requires the FS modifier on the E/M code. This flag:

• Indicates both a physician and NPP participated in the service
• Enables CMS to track utilization of split/shared billing
• Does not affect reimbursement but supports claims integrity

Keep in mind:

• Some commercial payers do not recognize FS
• Others still follow older billing standards (e.g., face-to-face models or NPP credentialing limitations)
• Payer-specific guidelines must be reviewed regularly

When working with EDs across multiple health systems, we consistently see two high-risk documentation gaps:

 

1. Missing or conflicting attestations:

• The physician says they provided the majority of care
• The NPP says the same
• Neither supports this statement with specific notes or an attestation

This creates uncertainty for coders and potential exposure to payer audits.

 

2. Inconsistent billing practices across payers

• Medicare requires FS
• Some commercial payers don’t allow split/shared billing
• Others won’t credential NPPs, forcing to bill under the physician—whether they led care or not

Without an organized, payer-specific approach, billing can become noncompliant—without anyone realizing it.

The most successful EDs we support don’t leave this to chance. They do the following:

 

Use smart workflows

• EHRs flag when physician attestation is needed
• Policies define when physicians must lead care (e.g., high ESI levels, complex presentations)

Standardize attestation language

• Dot phrases or smart texts make attestation easy
• Providers use templates but customize them to their specific contribution

Generate operational reports

We help teams regularly review:

• The volume of split/shared encounters
• The billing provider mix (physician vs. NPP)
• The financial difference between physician- and NPP-billed services

These reports allow operational and clinical leaders to spot trends, address documentation gaps and reduce lost revenue.

Split/shared billing isn’t new. But its enforcement is evolving—and it’s now a top compliance focus for CMS and commercial payers alike.

This doesn’t mean ED workflows need to slow down. With the right tools and structure, attestation can be low lift and high impact.

If you lead an emergency department, here’s where to focus:

• Clarifying the policy for your teams
• Standardizing attestation tools to reduce friction
• Auditing your billing trends to identify gaps
• Tailoring your approach to your payer landscape

When documentation accurately, clearly and consistently reflects the care being delivered, everyone benefits.

• Your teams get credit for their work
• Your organization protects its revenue
• Your compliance risk stays exactly where it should be