Molecular and cell biology

Flow Cytometry interview questions

Cell-level fluorescence measurements, gating, compensation and instrument controls.

6 questions, each with a worked answer

Why are fluorescence compensation controls important? Fundamentals Concept
How would you design a defensible gating strategy? Intermediate Scenario
Why is fluorescence-minus-one not the same as an isotype control? Intermediate Concept
What can make an apparently rare cell population an artefact? Intermediate Scenario
How would you design a flow panel with coexpressed markers? Intermediate Scenario
How would you compare cell frequencies when parent population sizes differ? Intermediate Scenario

About Flow Cytometry

Flow cytometry measures light scatter and fluorescence from single cells as they pass a laser one at a time, thousands per second. It tells you how many cells in a sample carry a marker and how strongly, so populations can be counted, characterised or sorted. The hard parts are panel design, compensation for overlapping dyes and gating that someone else could reproduce.

It is central to immunology, cell therapy manufacturing and many clinical and quality assays.

Fundamentals: 1
Intermediate: 5

What these questions test

Design cytometry gates: Create defensible gating strategies and assess compensation or background.

References

NCBI Bookshelf. National Library of Medicine. ncbi.nlm.nih.gov/books.
pmc.ncbi.nlm.nih.gov/articles/PMC11115438.

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.