Lab Technician interview questions and answers

The commonly followed order for evacuated tubes is blood culture bottles first, then the light blue citrate tube for coagulation, then plain or gel serum tubes with a red or gold top, then the green heparin tube, then the lavender EDTA tube, and finally the grey fluoride tube used for glucose. It matters because additives can carry over on the needle into the next tube. For example, EDTA carried into a serum tube can falsely raise potassium and lower calcium, and blood cultures go first to avoid contamination. I always follow the order set in our lab’s SOP, which is usually based on the CLSI guideline.

Before collecting, I ask the patient to tell me their full name and date of birth, rather than asking, Are you Mr Sharma? I match these with the request form and the wristband for inpatients. I label the tubes in front of the patient immediately after collection, never before, with the name, a second identifier such as the UHID or lab number, the date and time of collection and my initials, or with the barcode label generated by the LIS. I check that the label matches the form once more before leaving. If any detail does not match, I stop and clarify with the ward or reception before collecting.

Common reasons are an unlabelled or mislabelled sample, a label that does not match the request, a haemolysed sample for tests affected by haemolysis, a clotted EDTA sample for blood counts, an underfilled citrate tube, the wrong tube type, insufficient volume, a leaking container, or a sample that has exceeded its stability time or was transported at the wrong temperature. When I reject one, I follow the lab’s rejection SOP: I record the reason in the LIS and the rejection register, inform the ward or collection centre promptly so a repeat sample can be taken, and never relabel a sample myself. For irreplaceable samples, I ask the pathologist before deciding.

At the start of each run or shift, as the SOP says, I run the control materials, usually two or three levels, after checking their lot number and expiry and bringing them to room temperature. The values are plotted on a Levey-Jennings chart against the mean and standard deviation set for that lot. If one control is outside two standard deviations, that is a warning, and I look at the trend. If one is outside three standard deviations, or two in a row are outside two on the same side, I reject the run. Then I do not release patient results. I check the reagent, calibration and instrument, correct the cause, rerun controls and record everything in the QC log.

Internal QC checks that our analyser gives consistent results day to day using known control material. External quality assessment checks accuracy against other labs. An outside provider sends samples with unknown values a few times a year. We test them exactly like patient samples, in routine runs and by routine staff, and send the results back. The provider compares our results with the peer group and gives a score. If we are outside acceptable limits, we investigate the cause, such as calibration, reagents or a transcription error, record the corrective action, and keep it for the NABL assessor. I have handled EQAS samples for biochemistry in my current lab.

Under the Bio-Medical Waste Management Rules followed in India, waste is segregated at the point of generation. Yellow bags take infectious and soiled waste such as cotton and dressings contaminated with blood, and microbiology waste like used culture plates after pre-treatment as required, usually by autoclaving. Red bags take contaminated recyclable plastic such as tubing, gloves, and plastic tubes without needles. Sharps such as needles and lancets go into a white, puncture-proof, translucent container. Broken or discarded glassware and glass slides go into the blue puncture-proof container. I never recap needles, and I keep containers no more than three-quarters full before sealing.

I would stop the work safely, let the wound bleed freely without squeezing it, and wash it at once with soap and running water. I would not scrub, suck or apply bleach to the wound. Then I would report it immediately to my supervisor and the infection control or occupational health team, as the hospital policy says, because post-exposure prophylaxis decisions need to be made quickly. I would note the source patient’s details, if known, so their status can be checked with consent. I would also fill in the incident report. Afterwards, I would follow the advised testing schedule and look at how the injury happened to prevent a repeat.

I prepare a thin smear on a clean slide, let it air dry and heat fix it by passing it through the flame a few times. Then I flood it with crystal violet for about a minute and rinse with water. Next I add Gram’s iodine, which acts as a mordant, for about a minute and rinse. Then I decolourise with acetone or alcohol for a few seconds until the run-off is clear, and rinse quickly, because this is the step where over-decolourising causes errors. Finally I counterstain with safranin, rinse, dry and examine under oil immersion. Gram-positive organisms appear purple and Gram-negative organisms appear pink or red.

I check that the tubes are capped and not cracked, and that I am using the right buckets or adaptors. I balance the load by placing tubes of equal weight opposite each other. If I have an odd number of samples, I add a balance tube filled with water to the same level. I close the lid fully before starting and set the speed and time as per the test SOP. I never open the lid while the rotor is spinning. If I hear unusual noise or vibration, I stop the machine. After the run I check for any broken tube before removing samples, and clean spills with disinfectant as per protocol.

First I check that the result is genuine: the sample identity, the sample quality such as haemolysis or clots, that QC for the run passed, and whether there is a previous result to compare. If needed, I rerun the sample. Then I follow the lab’s critical value policy, which lists the tests and limits set by the pathologist. I inform the treating doctor or the ward nurse within the time the policy sets, ask them to read the result back to me, and record the time, the person’s name and my name in the critical value register or LIS. If I cannot reach anyone, I escalate to the pathologist on duty. I do not wait for the report to be printed.

I follow the stability and storage requirements written in our SOP for each test. Samples from collection centres travel in sealed, leak-proof containers with absorbent material and the right temperature, using cool packs where required, and with a temperature log. On arrival, I check the transport time and temperature record and the condition of samples, and note any problem. Serum for some tests needs to be separated within a set time, so I centrifuge promptly. Samples kept for later testing or repeat checks go into the labelled refrigerator or freezer rack, and I record the fridge temperature twice a day. Out-of-range temperatures are reported and the affected samples assessed before testing.

During a night shift, a patient’s haemoglobin came out much lower than the previous day’s result, with no note of bleeding. The delta check flagged it. I looked at the sample and saw it was partly clotted, which can give a falsely low count. I informed the ward nurse, explained the problem and requested a fresh sample. The repeat was close to the earlier value. I recorded the rejection reason and the communication in the LIS. The next week, I shared the example at our team meeting and suggested that night collection staff mix EDTA tubes gently straight after drawing.

One morning the level-two glucose control on our chemistry analyser came out above the limit, with about sixty OPD samples waiting. The front desk was getting calls. I did not run patient samples. I checked the control lot and found that it had been opened and kept longer than its stated stability after opening. I opened a fresh vial, and the controls were within range. I then ran the samples and told the front desk the expected delay. I documented the failure and the corrective action. Afterwards, I started labelling every opened control vial with the opening date and discard date.

A young woman at our collection centre told me she had fainted during a blood test before. I made her lie down on the couch rather than sit in the chair, kept talking to her about her day, and asked her to look away. I prepared everything before applying the tourniquet so the procedure was quick. After collection, I asked her to stay lying down for a few minutes and gave her water and a biscuit. She felt fine and left after ten minutes. I noted on her record that she should be bled lying down next time, so other staff would know.

A senior colleague used to skip the second check of patient details when registering samples during rush hours, saying it wasted time. I was worried about mix-ups. I did not argue in front of others. During a quiet time, I showed him the SOP section and mentioned a mislabelling near-miss from the previous month. He said the step was slow because labels were printed one by one. Together we suggested to the lab manager that labels be printed in batches at registration. The manager agreed, the check became faster, and he started following it.

When our lab installed a new haematology analyser, I was one of two technicians trained by the company engineer. I took notes during the training, then read the operator manual for the maintenance and error sections. During the validation period we ran patient samples on both the old and new analysers and compared results, as the pathologist had planned. I made a one-page quick guide for daily start-up, QC and shutdown, which the pathologist approved and put near the machine. Within two weeks I was training the night staff on it.

I did my six-month internship at a district hospital lab, rotating through haematology, biochemistry, microbiology and the collection room. In collection, I drew blood under supervision and later on my own for routine OPD patients. In haematology, I prepared and stained peripheral smears and ran samples on the cell counter. In biochemistry, I helped run daily QC and loaded samples. In microbiology, I did Gram stains and plated urine samples, but culture reporting was done by seniors. The biggest lesson was how strict the labelling and QC steps were, and why.

Yes, I am comfortable with night duty. I understand that emergency and ICU samples need a lab running at all hours, and that the night technician often works with less supervision, so I stay strict about QC and critical value reporting. I have done night postings during my internship. I live near the hospital, so travel is not a problem. I would only ask that the roster be shared in advance, and that I get the usual rest day after a run of night shifts.

I have a DMLT and one year of experience at a diagnostic centre, where I handled collection, haematology and biochemistry. Based on that and the usual range for technicians in this city, I am hoping for a reasonable increase on my current salary. I can share exact figures. I would also like to know about night shift allowance, PF and health benefits. Working in a NABL-accredited lab is important to me for learning, so I am flexible if the role offers good training.

In my current lab at a small nursing home, I handle everything, from collection to reporting, which has taught me a lot. But we have limited quality systems and no accreditation. Your lab is NABL accredited, runs automated analysers and has a structured QC and EQAS programme, which is where I want to grow. I also want to specialise further, ideally in biochemistry or immunoassays. I have read about your home collection network, and I am happy to start in any section and earn more responsibility.