The FDA actively regulates medical devices intended for diagnostic use. Diagnostic kits intended for diagnostic use face the full panoply of FDA regulation. In sharp contrast, research use only (RUO) products are essentially unregulated. In fact, although RUO products are often discussed as though they are a kind of medical device, RUOs are not devices at all.
A commercially important class of products, RUOs are defined very briefly by FDA regulations. RUO products are described as products “in the laboratory research phase of development and not represented as an effective in vitro diagnostic product.” This definition has created some uncertainty as to what products fall into the RUO category.
The same regulation establishing the RUO category requires that RUO products bear the following labeling statement: “For Research Use Only—Not for use in diagnostic procedures.” Although not authorized by the regulation, many companies have shortened the statement to just the first clause. FDA regulations do not prescribe any other restrictions or limitations on RUO products beyond this labeling statement. Thus, FDA regulations define the category and prescribe labeling, and nothing more.
Given that RUO products are not intended to diagnose “a disease or other condition,” it is not clear that they are even subject to FDA’s jurisdiction. The intended use of an RUO product—research, not diagnosis—presumptively removes it from the definition of a device and FDA’s authority.
In any event, aside from bearing the mandated statement, RUO products are not regulated by the agency. For example, they do not need to be listed with FDA or comply with the Quality System Regulation (QSR). They can be sold without any FDA clearance or approval. As a practical matter an RUO is essentially unregulated by FDA.
Over the years, the paramount regulatory issue for products bearing the RUO label has been whether or not they actually do belong within the RUO category. There have been multiple instances in which RUO products have become widely used by laboratories for clinical applications. There have also been a number of occasions where companies have labeled products as RUO but then promoted them for diagnostic use. In some instances, companies have made specific diagnostic claims for their assay or instrument but still labeled the product as RUO.
Biomarker kits are often labeled as RUO because it is not known whether the product has any clinical use or, if so, what that use might be. The assay’s developer may expect that a particular biological substance will be of some clinical value, but not be sure what that value is. Labeling a product RUO, allows it to get into the hands of researchers who can then evaluate whether the product may be potentially valuable for some specific diagnostic purpose.
Often, no clinical use is ever identified. Some assays maintain their true RUO status indefinitely. While the product may be helpful to researchers in understanding basic biological mechanisms, a diagnostic use may never be discovered.