Laboratory Assistant interview questions and practice.
Prepares samples, reagents and equipment, logs specimens and keeps the laboratory clean and stocked so tests can run smoothly.
No card for the taster. Full interviews are paid one at a time. Nothing renews.
Last reviewed
This page is still being written: no authored question bank for this competency family. The role is fully supported in the interview itself; only the published question bank is outstanding.
What interviewers for Laboratory Assistant actually ask
The question bank for this role is still being written. These are the first three competencies in the model the interview is scored against.
Ensures specimens are correctly identified, collected, labelled, transported and stored, and rejects or flags samples that would give unreliable results.
Runs and interprets internal QC and external quality assessment, acts on out-of-control results before releasing patient results, and maintains ISO 15189 or SANAS readiness.
Reviews results for plausibility against the patient's history and previous values, and communicates critical values to the right clinician promptly with a documented read-back.
What they are really assessing
Interviewers rarely score whether you seemed nice. They score against a model like this one, usually without telling you it exists. Each competency has a weak, adequate and strong shape, and the difference is almost always the level of specific detail you volunteer without being asked.
Pre-analytical & specimen integrity
Ensures specimens are correctly identified, collected, labelled, transported and stored, and rejects or flags samples that would give unreliable results.
- Weak
- Describes pre-analytical checks as 'the label matches the form'; cannot name common rejection criteria or give an example of a mislabelled or haemolysed sample handled.
- Adequate
- Names rejection criteria and describes rejecting a sample and informing the ward, but not how they handled pressure to run it anyway or the follow-up to reduce recurrence.
- Strong
- Describes a specific pre-analytical failure (wrong tube, delayed transport, identity mismatch), the rule applied, the conversation with the clinician who wanted it run, the recollection outcome, and the trend data or training that followed.
Quality control & accreditation
Runs and interprets internal QC and external quality assessment, acts on out-of-control results before releasing patient results, and maintains ISO 15189 or SANAS readiness.
- Weak
- Describes QC as 'running the controls each morning'; cannot explain Westgard rules, what to do with a failed control, or what an audit non-conformance looked like.
- Adequate
- Explains QC rules and describes a failed run they repeated, but cannot describe root cause investigation or what happened to results released between the last good QC and the failure.
- Strong
- Describes a specific QC or EQA failure: the rule violated, the root cause found (reagent lot, calibration, pipette), the look-back on patient results, the corrective action record, and how it held up at the next audit.
Result validation & critical communication
Reviews results for plausibility against the patient's history and previous values, and communicates critical values to the right clinician promptly with a documented read-back.
- Weak
- Releases whatever the analyser produces; cannot name critical value thresholds for common analytes or describe a phone-out.
- Adequate
- Uses delta checks and knows critical thresholds, and describes phoning a critical result, but not what they did when they could not reach the doctor or when a result did not fit the clinical picture.
- Strong
- Describes a result that looked wrong (delta failure, impossible combination), the checks they did before release, the critical phone-out with read-back and escalation when unreachable, and how it was documented.
Analytical troubleshooting & equipment
Diagnoses analyser and assay problems methodically, performs maintenance and calibration, and manages downtime so that turnaround times and patient care are protected.
- Weak
- Describes troubleshooting as 'calling the service engineer'; cannot describe an instrument problem they resolved themselves.
- Adequate
- Describes maintenance routines and one fault they isolated (e.g. a probe, a reagent), but cannot explain how downtime was managed or how they decided results were trustworthy again.
- Strong
- Describes a specific fault: the symptoms, the systematic isolation of cause, the downtime plan (backup analyser, referral, prioritised samples), verification before resuming, and the maintenance change afterwards.
Protocol adherence & GCP
Follows the study protocol and Good Clinical Practice, documents deviations honestly, protects participant safety and consent, and manages source data for audit.
- Weak
- Describes GCP as 'a certificate we do'; cannot describe a protocol deviation, an adverse event report or what informed consent requires.
- Adequate
- Describes the consent process and reporting a deviation, but is vague on timelines for serious adverse events or how source data is kept audit-ready.
- Strong
- Describes a specific deviation or SAE: how it was identified, the reporting timeline met, the discussion with the PI and sponsor, the corrective action plan, and what a monitor or auditor found afterwards.
Biosafety & sample handling
Applies biosafety levels, PPE, sharps and spill procedures, and waste management consistently, and reports exposures and near-misses.
- Weak
- Describes safety as 'wearing gloves and a coat'; cannot describe a spill or exposure procedure or has never reported an incident.
- Adequate
- Describes spill and needle-stick procedures correctly and an incident they were involved in, but the reporting and follow-up (PEP, root cause) is vague.
- Strong
- Describes a specific exposure or spill: immediate actions, reporting, the root cause (technique, equipment, fatigue), the change made, and how they challenged a colleague's unsafe practice.
Documentation & data integrity
Keeps records that are attributable, legible, contemporaneous, original and accurate, whether in a LIMS, worksheet or case report form, and never backfills or alters without a trail.
- Weak
- Describes records as 'filled in at the end of the day'; sees corrections as tidying up; cannot describe an audit trail or a data discrepancy they resolved.
- Adequate
- Follows ALCOA principles and can describe correcting an entry properly, but cannot describe a data integrity concern they raised or found.
- Strong
- Describes a data discrepancy or integrity concern they found (transcription error, missing signature, backdated entry), how they raised it, how it was investigated, and the process change to prevent recurrence.
Reading the questions is the easy half. Try answering three of them out loud, to someone who follows up.
Try 5 minutes freeWhat your 30 minutes covers
The same shape as a real first-round interview, pitched at junior Laboratory Assistant and scored throughout.
Warm-up, then Motivation & fit
Build rapport, settle nerves, and get a short walk-through of your background. Why this role, why this employer, and what you are actually looking for.
Your experience
Two or three real situations from your CV in depth: context, what you did, what happened, what you would change.
Pitched at junior scope: registered technician, technologist or study coordinator: owns a bench, section or study site day-to-day, including QC, result release within authority, and documentation.
Role-specific questions
The core competencies and domain knowledge for the role, with follow-ups on anything vague.
Drawn from this role's domain: pre-analytical errors and sample rejection criteria, internal QC, Westgard rules and external quality assessment and iSO 15189, SANAS accreditation and non-conformance management, and the rest of the competency model.
Your questions, then Wrap-up
Your questions for the interviewer, and yes, they are assessed. Next steps and a clean finish.
What changes with seniority
The questions barely change between levels. What changes is the answer they will accept.
| Junior | Mid | Senior | |
|---|---|---|---|
| Scope of ownership | Registered technician, technologist or study coordinator: owns a bench, section or study site day-to-day, including QC, result release within authority, and documentation. | Senior technologist or senior coordinator: responsible for a section's quality, method verification, audits and training, and for several studies or a site. | Section head, quality manager or clinical research manager: accountable for accreditation status, turnaround times, staffing and compliance of a section or research unit. |
| Tolerance for ambiguity | Handles routine deviations and QC failures per SOP; escalates unusual results, instrument faults and protocol grey areas. | Investigates root causes and decides on corrective actions; interprets accreditation and GCP requirements for new situations. | Decides how to respond to inspections, serious incidents and sponsor findings; balances throughput, cost and quality. |
| People leadership | May supervise students or phlebotomists. | Trains and competency-assesses juniors; allocates work. | Line-manages technologists or coordinators; handles performance and discipline. |
| Who they deal with | Section supervisor, clinicians, principal investigator, sponsor monitors. | Laboratory manager, pathologists, quality manager, sponsors, ethics committees. | Laboratory director, hospital or CRO management, SANAS assessors, regulators, sponsors. |
What your report would say
Every competency above scored from your own answers, the sentence that cost you quoted back, and your weakest answers rewritten the way a strong Laboratory Assistant would have said them.
- Describes a result that looked wrong (delta failure, impossible combination), the checks they did before release, the critical phone-out with read-back and escalation when unreachable, and how it was documented.
The format, not a result. Scores on your report come from what you actually said.
Is the AI interviewer realistic? See a full sample report