Rising Denials for CPT 87798 in 2026: What Laboratories Need to Know

March 27, 2026
Billing, Business, Coding, Compliance, Labs

Denials for CPT 87798 billing (infectious agent detection, NOS) are rising sharply—and this is not a random fluctuation.

Since mid-February, laboratories across the U.S. have seen a consistent spike in denials, particularly from Medicare Administrative Contractors such as Novitas Solutions, NGS Medicare, and First Coast Service Options. Across multiple laboratories, a clear and repeatable denial pattern has emerged.

This is not routine payer variability.
This is the start of active enforcement.

 


A Code That Has Moved into Focus

For years, CPT 87798 operated quietly in the background of molecular diagnostics—a practical fallback when organism-specific codes were unavailable. Reimbursement was relatively stable, and the code was widely used across PCR workflows, multiplex panels, and laboratory-developed tests (LDTs).

That position has now changed.

Labs are increasingly encountering medical necessity denials, “experimental or investigational” determinations, and documentation-related rejections. The growing appearance of Remark Code N35—a utilization-based payment adjustment—is particularly telling. It signals that payers are not just reviewing claims, but actively responding to how frequently and in what context this code is being used.

What was once a stable revenue stream is now under active review.

 


Why This Is Happening Now

Payer behavior in laboratory medicine typically follows a recognizable pattern:

Utilization spike → silent monitoring → enforcement → policy formalization

CPT 87798 has now entered the enforcement phase.

All indicators point toward a targeted utilization review initiative, not a passive shift. CPT 87798 sits at the intersection of cost, ambiguity, and utilization—making it a natural focus area for payers.

It is a high-cost, high-visibility code, often used as a fallback, and closely tied to multiplex testing, LDT utilization trends, and broader molecular lab billing challenges. What was once acceptable flexibility is now being interpreted as ambiguity—and ambiguity is no longer tolerated.

 


What’s Really Driving CPT 87798 Denials

This shift is not being driven by a single factor, but by multiple forces converging at once.

There is a clear push toward greater coding specificity. Payers increasingly expect claims to reflect exactly what was tested and why. When a non-specific code like 87798 does not provide that clarity, the burden shifts to documentation—and when that documentation falls short, the claim does not pass. This is one of the most common drivers of CPT 87798 reimbursement issues in 2026.

At the same time, automation is scaling enforcement. Claims are now being filtered through pre-adjudication edits and algorithmic review systems. This is why denial patterns are appearing suddenly and consistently across multiple MACs—it is systematic, not manual.

There is also growing scrutiny around multiplex and panel-based billing. When CPT 87798 is used multiple times within a single encounter—particularly across different organisms—payers are increasingly treating those claims as duplicative, bundling them, or denying additional units altogether.

Overlaying all of this is a deeper structural shift toward test-level accountability. Frameworks like MolDx—and increasingly commercial payer policies—are moving beyond CPT codes and expecting clear identification of the actual test performed. CPT 87798, by design, does not provide that transparency, making it inherently vulnerable in this environment.

 


From Claim-Level Issues to System-Level Risk

What makes this moment different is that denials are no longer isolated—they are pattern-driven.

Payers are tracking how frequently CPT 87798 is used, under what circumstances, and whether documentation consistently supports it. Labs with higher reliance on the code or inconsistent justification are more likely to face repeated denials, prepayment reviews, and audit escalation.

This shifts CPT 87798 from a billing tool to a risk signal within broader molecular diagnostics reimbursement workflows.

 


The Impact on Laboratories

The impact is already visible: a gradual but sustained increase in denials, increased payer scrutiny and claim reviews, higher audit exposure and compliance risk, and measurable revenue compression if not proactively addressed.

This is not a short-term disruption—it is the early stage of formal policy enforcement.

 


What Happens Next

If the current trajectory holds—and all indicators suggest it will—the next phase is predictable:

  • Formal policy updates
  • More explicit coverage limitations
  • Expanded audit activity

In other words, what is now being enforced quietly will soon be codified.

Labs that wait for policy clarity may find themselves reacting too late.

 


The Path Forward

The response required here is not tactical—it is strategic.

Labs need to move away from using CPT 87798 as a fallback and ensure that its use is intentional, justified, and supported by strong documentation. That documentation must clearly establish medical necessity and align with diagnosis coding.

Equally important is utilization visibility. Labs must track ordering patterns, frequency, and payer responses to identify risk signals early. Internal audits should be proactive, not reactive—designed to catch gaps before payers do.

 


Beyond Compliance: Building a Resilient Revenue Model

This trend reflects a broader shift in laboratory billing—from volume-driven processes to data-driven, audit-ready systems.

Success increasingly depends on:

  • Real-time visibility into billing performance
  • Intelligent workflows that flag risks early
  • Integration between clinical, operational, and billing data

Automation and analytics are no longer optional—they are foundational to navigating payer scrutiny and maintaining financial stability.

 


Conclusion: A Defining Moment for Laboratories

CPT 87798 is becoming a focal point for payer oversight—and a precursor to formal policy enforcement.

This is not just about one code. It reflects a broader transformation toward tighter control, greater specificity, and structured reimbursement in molecular diagnostics.

Labs that proactively adapt will reduce denials, protect revenue, and strengthen long-term operations. Those that delay may find themselves reacting under increasing pressure in a system that has already moved forward.

 


💬 Let’s Connect

Are you seeing increased denials or payment adjustments for CPT 87798?

Now is the time to compare notes, align strategies, and stay ahead of shifting payer behavior. Let’s connect to share insights and build a more resilient, audit-ready approach together.

 

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