Sponsors should consider whether a study exhibiting the factors relevant to the exercise of enforcement discretion will generate sufficient data to support the product application they are considering. Although FDA does not intend to reject data from a study exhibiting the factors solely because it was conducted without complying with the informed consent requirements found in 21 CFR part 50, FDA also does not guarantee that the data generated from a study with those characteristics will be sufficient to support a premarket clearance or approval. FDA may determine that additional clinical information is important in order to evaluate test results. For some studies, masking of clinical information may be problematic and may bias data collection. Sponsors should understand that by choosing to conduct an investigation without informed consent, even in a manner consistent with this guidance, they accept the risk that they may not be able to provide sufficient information to satisfy FDA's premarket review needs.

For reference to the characteristics mentioned, see here.