Discovery and biotherapeutics

Assay Development interview questions

Developing reliable, fit-for-purpose experiments and measurement methods.

6 questions, each with a worked answer

About Assay Development

Assay development is building a measurement that answers a specific question reliably enough to base decisions on. It means choosing a format, optimising conditions, setting controls and showing precision, accuracy, range and robustness. What counts as good enough depends on the purpose: a screening assay, a release test and a clinical biomarker assay have very different bars.

Most of the work is finding and removing the sources of variation that do not come from the biology.

Fundamentals: 1
Intermediate: 3
Advanced: 2

What these questions test

Build assay validation plans: Define precision, specificity, working range and fit-for-purpose acceptance criteria.

References

NCBI Bookshelf. National Library of Medicine. ncbi.nlm.nih.gov/books.
ema.europa.eu/en/scientific-guidelines/ich-q2r2-validation-analytical-procedures.
ncbi.nlm.nih.gov/sites/books/NBK83783/?report=classic.
fda.gov/regulatory-information/search-fda-guidance-documents/q14-analytical-procedure-development.
ncbi.nlm.nih.gov/sites/books/NBK126174.

Practice material written by TheBench.Bio and checked against the references above, reviewed October 23, 2026. Written to practise with, not collected from real interviews.