Understand Translational Research Tools


In the context of medical research, a biological assay (bioassay) is a procedure that allows a biological process to be quantified.  Bioassays are important in the development of drugs and many biologics.

  • In early therapy development, bioassays help determine which potential compounds have a higher likelihood of being an effective treatment.
  • Bioassays can be cell-free (or biochemical) or cell-based procedures.
  • High-throughput assays (also called high-throughput screenings) utilize advanced technology to miniaturize and automate the bioassay so that large libraries of potential therapies can be screened very quickly. For example, the National Center for Advancing Translational Sciences (NCATS) qHTS can screen more than a million compounds a day.
  • Bioassay procedures usually include applying a set of reagents. A reagent is a substance or compound added to a system to cause a chemical reaction or added to test whether a reaction occurs. 
  • The set of reagents used in a bioassay produces a detectable signal that can quantify the target biological activity. Signals that can be measured quantitatively include:
    • Absorbance
    • Fluorescence
    • Luminescence
    • Radioactivity
  • Required qualities of bioassays include:  
    • Reproducibility
    • Reliability
    • Robust
    • Biologically relevant
  • Knowing the biological pathway underlying your disease can help researchers develop a more comprehensive bioassay.
  • Researcher(s) developing bioassays for your disease may benefit from knowing about NCATS Assay Guidance Manual, a free, best-practices online resource that is devoted to the successful development of robust, early-stage therapy discovery assays.


Assay Guidance Manual National Center for Advancing Translational Sciences (NCATS) (link)
CDER Biomarker Qualification Program U. S. Food and Drug Administration (FDA) (link)
Cell and Animal Models
Animal Model Qualification Program U. S. Food and Drug Administration (FDA) (link)
NCI Best Practices for Biospecimen Resources National Cancer Institute (NCI) (link)