Contributed Commentary by Cody Aplin and Tami Munn
September 16, 2026 | Since last year’s landmark legal ruling that the U.S. Food and Drug Administration’s attempted oversight of laboratory-developed tests was not supported by current legislation, the research-use-only (RUO) pathway has emerged as an increasingly attractive alternative to the FDA-regulated in vitro diagnostic (IVD) route for diagnostic companies. There’s nothing wrong with that, provided that analytical rigor and performance are not compromised throughout the development and validation processes.
In practice, the use of RUO assays often extends beyond the research bench. They are routinely used with patient samples for biomarker discovery and translational research, in clinical trials to measure drug response, and in the development of IVDs and laboratory-developed tests. Although an RUO assay may never directly contribute to a diagnosis, its data can influence research and clinical decisions that ultimately affect patient care.
RUO assays employed as clinical trial assays or as laboratory-developed tests (LDTs) should be designed with the capability to meet the analytical performance standards of an IVD test, even when there are no immediate plans to pursue IVD clearance. Although many professionals at diagnostic companies may advocate that this approach adds unnecessary time and cost to the validation phase, there are two compelling reasons to adopt it.
First, designing up to IVD-level performance standards from the outset reduces the risk of costly redevelopment if the assay later advances toward diagnostic or LDT use. Second, the regulatory landscape for diagnostic tests remains uncertain. While there is currently greater flexibility in the U.S., regulatory requirements are becoming increasingly stringent in Europe. In this environment, it is prudent to expect the unexpected.
As a result, preparing for an IVD pathway, regardless of whether the plan is to pursue it immediately, sets companies up for success should regulations change. After all, transitioning from an RUO pathway to an IVD pathway often requires expensive, time-consuming bridging studies that can erase any early savings gained by developing the assay without IVD-level design foresight.
While the rationale for developing an IVD-capable assay is compelling, execution remains challenging. Many companies may lack the necessary resources and expertise to develop an IVD assay. Even those that have been through the process previously might decide that certain projects don’t merit deploying those internal resources.
In these cases, a partnership approach can be the way to go. There’s an entire ecosystem of service companies specializing in the development and validation of immunoassays on behalf of other organizations. Like contract research partners, they can handle specific tasks—such as sourcing key components of an assay or designing an assay to minimize cross-reactivity between targets—or manage the entire process, from assay design to validation to manufacturing. The right partner brings more than extra hands. One with deep experience developing high-performing assays can help identify the specific gaps between RUO- and IVD-level performance early on and design the assay from the outset to close them rather than revisiting the work later.
Not all prospective partners are created equally. Identifying the right partner involves examining a number of critical elements. The list below is not exhaustive, but it should provide a strong starting point for any partnering decisions.
Component supply. Whether it’s generating reagents, sourcing proteins, or customizing antibodies, ensuring a steady supply of all components needed in an assay is essential not just in the development and validation process but also in preparing for commercialization. A reliable partner can eliminate the complexity of sourcing components from multiple vendors, streamlining the process to a single partner for the entire assay development cycle.
Integrated approach. While it’s not impossible to select different vendors for different stages of assay development and validation, having a single partner for the entire journey can simplify the process and avoid extraneous costs associated with redundant tasks. A partner with antibody, reagent, development, manufacturing, and commercialization experience can handle everything, including extensive interference and characterization testing, as well as downstream manufacturing.
Technical prowess. This may seem too obvious to be worth mentioning, but a good partner should have deep technical expertise for assay development to ensure optimal performance and to reduce lot-to-lot variability. Beyond core scientific expertise, prospective partners should be evaluated on less obvious capabilities. Can this partner develop successful assays using platforms from other companies? Does this partner have deep familiarity with key characterization tools for components used in the immunoassay workflow? For example, a partner that maintains its own large, well-characterized catalog of antibodies and recombinant proteins, rather than sourcing them secondhand, paired with in-house expertise in techniques like capillary isoelectric focusing, can move an assay from concept through characterization without ever handing it off to a third party.
Regulatory experience. Even if the plan is to stick with an RUO test, any partner should have deep expertise in diagnostic regulations and guiding tests through review in various markets. One way to check this is to ask about the partner’s track record helping other companies navigate regulatory review and whether their team understands what FDA and international regulators expect at each stage of development. For an IVD-capable assay, having this expertise means the partner will be able to provide guidance and anticipate the studies and documents that would be required for regulatory review, if needed.
Checking all these boxes can help narrow the search for a great diagnostic development partner with a successful track record. With mounting pressure on diagnostic companies to expand their menus, especially by adding niche tests that may not bring in substantial revenue on their own, the value of a partnership approach has never been greater.
The partnership model delivers benefits on two fronts: it can accelerate development and validation timelines while reducing the risk of a costly redesign if an assay later becomes a clinical or diagnostic candidate. By pursuing an IVD-capable development strategy, even for assays initially launched as RUO products, companies can position themselves to weather regulatory changes while delivering robust, well-characterized products to the market.
Cody Aplin, Ph.D., is a scientist at Bio-Techne with expertise in protein science, biophysics, and chemical biology, working at the intersection of biomolecular science and diagnostic technologies. He can be reached at cody.aplin@bio-techne.com.
Tami Munn is a senior research and development scientist with experience in RUO and specializing in IVD assay development at Bio-Techne. She can be reached at tami.munn@bio-techne.com.