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Medical Laboratory Technician interview questions and how to answer them

A lab manager interviewing an MLT is picturing you alone on nights with a trauma rolling in. Every question is really asking the same thing: will you release a result you shouldn't, or sit on one you should call? Here's what they ask, why, and what a hireable answer sounds like.

11 questions7 minute read

Part 1

1.Your chemistry QC just failed and the ER is calling for a troponin. What do you do?

Why they ask

This is the core tension of the job. They want to know you won't release patient results on a failed run, even with a nurse on the phone.

How to answer

  • Stop reporting on that assay and tell the ER there's a delay and roughly why
  • Look at the Levey-Jennings chart and name which Westgard rule was broken, since a shift and a random error point to different fixes
  • Troubleshoot in order: rerun the control, check reagent lot and expiry, recalibrate, then maintenance
  • Send the specimen to a backup analyzer or the sister site if the fix will take too long
  • Once QC passes, rerun patient samples back to the last good QC and document everything

2.Walk me through calling a critical value.

Why they ask

A missed or botched critical call is one of the few lab errors that turns up in a patient safety review. Your process tells them whether you'll be a problem.

How to answer

  • Check the result makes sense first: specimen quality, delta check, whether it was already called
  • Call the licensed caregiver responsible for the patient, not whoever picks up the phone
  • Have them read back the patient name, identifier and value
  • Document who you told, when and the read-back in the LIS
  • Escalate per policy if you can't reach anyone

3.A potassium comes back very high on a patient whose last result was normal. What are you thinking?

Why they ask

It tests whether you question numbers or just release them. Hemolysis, EDTA contamination and a line draw can all fake a dangerous result.

How to answer

  • Check the hemolysis index and look at the tube
  • Look for signs of contamination, such as a low calcium alongside it
  • Ask how it was drawn if you suspect an IV line or a hard stick
  • Request a recollection instead of reporting a number you don't trust, and still follow critical value policy while you wait
4.The antibody screen on a type and screen is positive. What happens next?

Why they ask

Blood bank is where an MLT's limits matter most. They want to see you know the steps and when to hand off.

How to answer

  • Tell the floor that compatible blood may take longer, early, before they plan a surgery around it
  • Run the antibody panel per your lab's procedure and check the patient's transfusion history
  • Know when your lab sends the workup to a senior tech, the MLS tier or a reference lab
  • Mention emergency release procedures if the patient is bleeding and can't wait
5.A specimen arrives unlabeled, or labeled with a different name than the requisition. What do you do?

Why they ask

Wrong blood in tube is the error every lab fears. They're checking that you won't fix a label just to be helpful.

How to answer

  • Reject it and request a recollection, following your lab's rejection policy
  • Never relabel it yourself, even if the nurse swears it's the right patient
  • Know the rare exceptions, like a spinal fluid sample that can't be redrawn, and that they need a documented sign-off
  • File an occurrence report so the pattern gets seen

Part 2

6.The hematology analyzer flags platelet clumps on a CBC. How do you handle it?

Why they ask

Flags are where automation stops and you start. They want to hear that you look at a smear.

How to answer

  • Make and review a smear to confirm the clumps
  • Report per procedure with a comment, rather than releasing a falsely low count
  • Suggest a citrate tube recollection if EDTA clumping is likely
  • Mention the smear review criteria your lab uses for other flags too
7.Tell me about a time an instrument went down in the middle of a shift.

Why they ask

Analyzers break at the worst moment. They want someone who can troubleshoot, use backup and call service without freezing.

How to answer

  • Name the analyzer and the error, such as a clot in the sample probe or a failed pressure check
  • Say what you did first to keep stat work moving
  • Walk through the fix you tried and when you called field service
  • Close with how you documented it and warned the next shift
8.Which department are you strongest in, and which do you need the most help with?

Why they ask

Generalist labs rotate you through chemistry, hematology, urinalysis, coag and blood bank. They're sizing up how much training you'll need.

How to answer

  • Name a real strength with a detail from your rotation or last job
  • Be honest about your weakest bench, often blood bank or micro
  • Say exactly what you're doing to close the gap
  • Show you're willing to be a generalist, not only work one bench
9.Tell me about a mistake you made in the lab.

Why they ask

Everyone makes them. Labs run on people who report errors quickly, and this question finds the ones who hide them.

How to answer

  • Pick a real error, like a mislabeled aliquot or a result entered to the wrong test
  • Say how you caught it and how fast you told someone
  • Explain the corrected report and who you notified
  • Name what you changed in your own routine afterward
10.How do you treat proficiency testing samples?

Why they ask

Mishandling PT can get a lab cited during a CAP inspection. It's a quick way to see whether you know how a regulated lab works.

How to answer

  • Run them exactly like patient samples, on the same instruments by the usual staff
  • Never send them to another lab or compare answers with another lab
  • Mention that CLIA rules are the reason, without reciting them

Part 3

11.A nurse calls, angry that a stat result is late. How do you handle it?

Why they ask

Nights mean phone calls. They want someone who stays calm and gives useful information, not excuses.

How to answer

  • Look up the specimen in the LIS before you answer
  • Say where it is and a realistic time, or why it was rejected
  • Offer a fix, such as prioritising the rerun or asking for a recollect quickly
  • Keep the call short and polite, then follow up if you promised to

Questions to ask them

Ask at least two. It shows you're picking them too.

  • How many techs are on nights, and who do I call when blood bank gets complicated?
  • Which LIS and analyzers do you run, and how long is orientation on each bench?
  • How do you handle a failed QC when the ER is waiting?
  • What came up at your last CAP inspection?
  • Does the lab help pay for the MLS bridge, and do techs actually use it?

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