For years, in the US digital pathology has been cleared as one system. The scanner, image management system and display were reviewed together, and AI is being tied to a 510(k) cleared scanner. The evidence belonged to a fixed configuration.
Currently we see consolidation and laboratory developed tests growing. Laboratories are assembling systems.
Regulation on both sides of the Atlantic places more weight on the laboratory. FDA’s LDT rule was vacated [i], CMS and CDC have asked how CLIA should address AI-assisted interpretation [ii], and the IVDR sets the conditions for health institutions’ in house tests [iii].
As laboratories assemble increasingly complex diagnostic pathways, changes in scanners, stains, software, algorithms, or workflows can raise a fundamental question: does the evidence supporting performance still hold?
Change is no longer the exception.
It is the operating condition.
For companion diagnostics, this matters. In our previous post, we highlighted that four PD-L1 assays were approved across incompatible platforms, and that only three of the top 20 U.S. oncology laboratories offered all four [iv]. That was a problem of assays. As AI enters companion diagnostics, it becomes a problem of configurations.
Innovation stalls not because of the science, but because evidence generated in one configuration does not automatically hold in the next.
“Does the evidence still hold when the system changes, and when it moves to the next laboratory?”
We more and more think of this challenge as an evidence problem rather than a technology problem.
If every laboratory assembles its own diagnostic pathway, whose evidence will determine whether a patient receives therapy?
And when a component of the system changes, who is responsible for ensuring that the evidence still holds?
[i] FDA. Laboratory Developed Tests. Accessed September 26, 2026
[ii] CMS and CDC. Request for Information: CLIA Regulations (CMS-3485-NC). July 16, 2026
[iii] Regulation (EU) 2017/746, Article 5(5); Medical Device Coordination Group. MDCG 2023-1: Guidance on the Health Institution Exemption under Article 5(5) of Regulation (EU) 2017/745 and Regulation (EU) 2017/746.
[iv] Oliner K.S., et al. Challenges to Innovation Arising from Current Companion Diagnostic Regulations and Suggestions for Improvements. Clinical Cancer Research. 2025