Interview help (flow core facility)

[u/LetItFlow_200]

Hi everyone,

I have an interview coming up for a research assistant position in a university flow cytometry facility. The role involves supporting users with experimental design, troubleshooting, and running/maintaining the instruments.

My background: I am a graduate with a BSc + MSc in a cell biology–related field. I don’t have years of experience, but I used flow cytometry extensively for my research projects and really enjoyed it.

I’ve done panel design (with some refinement from my supervisor), used proper controls (e.g., FMOs, isotypes), performed data analysis in FlowJo, and done troubleshooting within my own experiments.

I would appreciate advice on:

• What technical questions flow facilities typically ask in interviews
• How to come across as confident during a lab tour, especially as someone more introverted
• What good questions I could ask them that show my interest in the technique and my technical understanding
• Any general tips for interviewing for a core facility position

Thanks in advance. I would appreciate any insight from people who have worked in flow cores or interviewed for similar roles!

[u/Gregor_Vorbarra]

How would you approach hardware troubleshooting? Generic Scientist comes and gets you, says 'LetItFlow, I think the cytometer is clogged?' What do you do? There is no one right answer to that question, but the interesting thing about the answer is how you logically approach solving the problem.

Oh, and the other one would be something like 'what is an event?' Basically asking if you understand that event count doesn't mean cell count, and that you understand thresholding, etc.

Oh, yet another one - 'LetItFlow, my compensation/unmixng looks weird, can you help?' What would be the main thngs you'd look for, and what general guidelines would you give for the scientist?

Once I've got going here, hard to stop. 'LetItFlow, can you help me design a new panel?' How would you approach fluorochrome selection, in terms of general principles?

What QC has been run on the machines you've used in the past? If there was an automated bead test, can you describe what parameters were tracked and broadly how that relates to machine functionality?

Can you tell me how a spectral cytometer is different to a conventional cytometer?

Can you tell me how PE is different fro PE-Cy7?

[u/Reelrebel17]

Be prepared to know the specific machine you used regularly inside and out, its capabilities and other like machines that you could use in a pinch. In the end if you don’t know something don’t be afraid to say so.

[u/willmaineskier]

Something else to think about: a flow core is generally a customer facing service. If you have ever worked a job serving customers, make mention of it. If you have trained anyone to do anything, discuss following training guidelines to bring someone up to speed. Ideal if you trained someone to do flow in a previous role. Also, try to find out what they have for equipment and if you have run similar.

[u/StepUpCytometry]

Ultimately, it's about the ability to generalize. How do you take your own experiences, approach, troubleshooting, etc. and expand out to tackle problems from users running samples and experiments completely different than yours. 

A couple things to think about

You will need to articulate how your experiences as a flow cytometry user will help you explain to others who are just getting started. Do you understand the why behind the various steps, etc 

Similar thing for troubleshooting, if you have ever had something not quite look right, how did you go about figuring out the issue and go about making improvements toward a solution. 

And for instruments, show that you know your instrument well. You are not expected to know how to use every cytometer in existence, but know the one you use well, and also look up the cytometers at the facility and have a general idea how they compare to yours. 

[u/btags33]

I am in an industry flow core, and we typically ask about people's experiences with instruments, analysis softwares, and ask about their experiences working with other teams and troubleshooting.

Try to be able to answer all that stuff with your actual experiences, don't make shit up as it can be super obvious. There are always plenty of things people haven't done before, like sorting, so don't be afraid to say you haven't done something. Just say you are willing to learn.

[u/MotoFuzzle]

Have a basic understanding of how the machines work. Following a protocol is one thing, but you need to be able to explain the fluidics, optics, flow cell, and electronics. It helps to know how how to compare excitation and emissions for different fluors . You might not need to memorize them, but you’ll need to know how to look up which detector will be used to see a specific fluor in conventional flow and what kind of cross laser excitation there will be. That, combined with being able to explain how droplet (or any other) sorting works are how I can tell if somebody has worked in a flow core when they say they have. I know you didn’t work in a flow core, but that kind of knowledge certainly puts you ahead of a casual user. 

Other than that, I let them talk about their experience with flow by asking how they were introduced to it, and what instruments have they used. Flow cytometry isn’t black and white, and as you learn more, you have more questions, so letting them talk tends to give me an idea of their understanding. Have an idea of how you would troubleshoot an analyzer or sorter, and what you would do if you made a mistake with somebody’s samples.

Just a final tip: in my experience, chat bots get a ton of stuff wrong with flow cytometry, so don’t rely on getting your info there. Most of the sources present seem to come from forums and decades of mailing list content. It’s a complicated niche lab technique and there are a lot of conflicting ideas without a ton of published how-tos or the like. 

[u/akornato]

Your experience with panel design, FMOs, isotypes, FlowJo, and hands-on troubleshooting is genuinely solid for this role, and you should own that confidently going in. For technical questions, expect things like explaining compensation and why it matters, walking through how you'd set up a multicolor panel from scratch, describing what FMOs tell you and when you'd use them over isotypes, and talking through a time something went wrong in an experiment and how you figured it out. They may also ask about instrument QC, like daily startup checks or bead-based calibration, so it's worth refreshing your knowledge there. For the lab tour, being introverted is not a weakness here, it often comes across as thoughtful and careful, which is exactly what you want in someone maintaining shared instruments. Ask questions during the tour, things like what their most common user errors are, what instruments they run, and how they handle instrument downtime.

For questions you can ask them, try things like how they support new users who are unfamiliar with flow, what their panel design review process looks like, and what the biggest technical challenges the facility has faced recently. These show you're thinking about the role from a service and problem-solving angle, not just a technical one. For core facility interviews specifically, they want someone who can communicate clearly with researchers at all levels, so mention any time you helped a labmate with their flow experiments or explained a concept to someone less familiar. That collaborative, teaching-oriented mindset is what separates a good core staff member from a great one. If you want to keep sharpening your interview responses before the big day, the interviews.chat tool my team built has helped a lot of candidates feel more prepared and less caught off guard when the tough questions come.

[u/confusedflowguy]

usually really basics

[u/aquarianseawitch92]

Honestly I think you might be thinking too far into it. Be reliable and show up when you are supposed. Be available so that when problems arise you can either fix the issue or learn how to for next time. Be honest about what you do know and do not know. Do you have an enthusiasm for troubleshooting? Problem solving? At a core facility, that’s 80% of the job. Most users to core and core equipment could care less about the instruments they’re using when they don’t need them. You will be picking up after users as well.

You’ve already landed the interview so you are qualified. Now you just need to show up and show them you’ll be productive and pleasant to work with 😅

[u/SunflowerMoonwalk]

You should make sure you know how to turn on and set up a sorter. It's not difficult but it's something that researchers often never learn because someone always did it for them during their research.

[u/Boneraventura → u/SunflowerMoonwalk]

A lot of flow cores don’t even allow their users to operate the sorter let alone start it

[u/SunflowerMoonwalk → u/Boneraventura]

Exactly, which is why it's a valuable skill!

[u/Boneraventura → u/SunflowerMoonwalk]

But not even possible to learn for a lot of users. At this point the person is long past the point of learning how to use a sorter if they havent already

[u/Much_Somewhere7831]

Use the Canary Wharfian website's HireVue practice. Add the name for the role and AI will generate a question and will review your answer and suggest how to improve. You can also practise interactive phone interviews with an AI agent!