Assay development and its key aspects

The ability to design, produce and run assays that are specific, robust and sensitive is crucial in all areas of biomedical research. Assay development plays a very important role in the fields of pharmacological, environmental and biological research. With the help of appropriate assays, researchers can analyze the effects of potential drugs under different conditions. On the other hand, if it is failed to do so, it can only compromise the integrity of the entire clinical trial.

Regardless of the particular molecule or specific application to be measured, several fundamental factors must be considered when developing a biological assay. It is also important to ensure that careful attention is paid not just to the assay itself, but also to the whole workflow that needs to be developed from sample preparation to analysis of the data quality delivered by the assay. The key aspects of the assay development discussed in this module are of general applicability.

Key aspects of the assay development:

When embarking on an assay development project, the researcher should ask several questions to define the exact requirements of the array.

What molecule and parameter are to be measured?

The first and foremost thing to do is to get a clear-cut idea about what molecule is to be assayed and what property of the molecule to be measured. This question has the fundamental importance and underpins all the subsequent assay development activities.

Source of the molecule:

It is also equally important to consider the source of the molecule that has to be assayed. Is the molecule to be measured is in a bodily fluid, such as urine or serum? Is the molecule to be measured in an organ obtained from a biopsy sample from a patient or an experimental animal? In this case, the source material would be the post-mortem tissue. The source of the molecule will determine the availability and quantity of the sample. Thus, the source of the molecule has a great influence on the assay development process.


Kowing the stability of the molecule that has to be assayed is also categorized as the important key aspect of the assay development. Is it stable or extremely unstable requiring special precautions o be taken during the collection and preparation of the assay? It is one important question that one has to work on during the assay development.  

Several samples to be assayed:

Considering how many samples will be needed for the assay development has its importance. If only a limited number of samples will be assayed then a labor-intensive, multi-step manual assay format may be perfectly acceptable. Conversely, if thousands or tens-of-thousands of assays are to be assayed, perhaps as part of a compound profiling exercise, it will be important to simplify, automate and streamline the assay process as much as lab resources allow.


The answers to all of the above questions concerning the molecule to be assayed will play an important role in helping the researcher decide on the most appropriate format for their particular needs. The assay development can also be done with the help of R&D pharma where scientific and technological issues can be resolved.