Automation and laboratory informatics

37 Kerala PSC Lab Technician Gr II practice questions on Automation and laboratory informatics, part of Biochemistry. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Easy

   In a semi-autoanalyser, which step is done by hand?

   1. APipetting sample and reagents
   2. BCalculating results from the standard
   3. CPrinting the report
   4. DReading the absorbance

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   Answer: A · Pipetting sample and reagents

   A semi-autoanalyser automates measurement: it aspirates the coloured reaction mixture into a flow cell, reads the absorbance, calculates the concentration from a stored standard or factor and prints the result. Sample and reagents are still pipetted, mixed and incubated by the technician. Pipetting errors are therefore the main source of imprecision. In a fully automated analyser, pipetting, mixing, incubation and reading are all done by the machine.

   • B: The analyser calculates the result from the stored standard or factor.
   • C: Printing is automatic.
   • D: Absorbance is read automatically by the photometer.

2. Question 2 · Easy

   The computer system that registers test requests, sends orders to analysers and stores results is the:

   1. ARadiology information system
   2. BPharmacy stock management system
   3. CPicture archiving system
   4. DLaboratory information system

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   Answer: D · Laboratory information system

   A laboratory information system (LIS) handles the laboratory's data from start to end: patient registration, test requests, barcode labels, worklists, analyser interfaces, result validation and reports. It also keeps records for quality control, billing and audit. A radiology information system and a picture archiving system (PACS) handle imaging, and a pharmacy system handles drug dispensing. The LIS is usually linked to the hospital information system.

   • A: A radiology information system manages imaging requests and reports.
   • B: A pharmacy system manages drug stock and dispensing.
   • C: A picture archiving system (PACS) stores and displays radiology images.

3. Question 3 · Easy

   In which type of analyser are samples pumped one after another through the same tubing, separated by air bubbles?

   1. ADry-chemistry analyser
   2. BCentrifugal rotor analyser
   3. CContinuous-flow analyser
   4. DDiscrete analyser

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   Answer: C · Continuous-flow analyser

   In continuous-flow analysers, such as the original Technicon AutoAnalyzer, samples and reagents flow through the same tubing, and air bubbles divide the stream into segments to limit mixing and carryover. All samples go through the same tests in sequence. Modern discrete analysers keep each sample-reagent mixture in its own cuvette, which allows random access and avoids most carryover. Centrifugal analysers mix and read many samples at once in a spinning rotor.

   • A: Dry-chemistry analysers use reagent slides, not a flowing stream.
   • B: Centrifugal analysers mix samples and reagents in a spinning rotor.
   • D: Discrete analysers keep each reaction in its own cuvette.

4. Question 4 · Medium

   In a bidirectional interface between an analyser and the LIS, the analyser:

   1. AOnly receives test orders from the LIS
   2. BPrints results for manual entry in the LIS
   3. COnly sends results to the LIS
   4. DReceives orders and sends back results

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   Answer: D · Receives orders and sends back results

   In a bidirectional interface, the analyser reads the barcode, asks the LIS (a host query) which tests are ordered and runs only those. The results then flow back to the LIS for validation without retyping. A unidirectional interface only sends results, so the tests must be programmed on the analyser by hand. Both steps remove transcription errors and save time.

   • A: In a bidirectional link the analyser also returns its results.
   • B: Manual entry is exactly what an interface is designed to avoid.
   • C: Sending results only is a unidirectional interface.

5. Question 5 · Hard

   On an analyser linked to the LIS, a ward patient's potassium is 6.8 mmol/L (4.1 yesterday). The LIS flags a delta check failure, and the hemolysis index is high. What should be done?

   1. APhone it at once as a critical result
   2. BRerun the same sample and then release it
   3. CRelease it with a note about hemolysis
   4. DHold the result and request a fresh sample

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   Answer: D · Hold the result and request a fresh sample

   A sudden rise from 4.1 to 6.8 mmol/L fails the delta check, and the high hemolysis index gives the likely reason: potassium has leaked from red cells lysed in the tube. The result does not reflect the patient's plasma, so it is held and the ward is asked urgently for a fresh, carefully collected sample. Rerunning the same tube only repeats the error, and releasing the result may lead to wrong treatment. Delta checks and serum indices are LIS and analyser tools for catching such pre-analytical errors.

   • A: Phoning a falsely high value may lead to needless and dangerous treatment.
   • B: The same hemolysed sample will give the same falsely high result.
   • C: A grossly hemolysed sample gives an unreliable potassium, even with a comment.

6. Question 6 · Hard

   One serum sample gives very low results for every test on an autoanalyser, while QC and the samples before and after it are normal. A fibrin strand is seen in the tube. What is the most likely cause?

   1. ADrift in the analyser calibration
   2. BAgeing of the photometer lamp
   3. CShort sampling caused by the fibrin clot
   4. DDeterioration of the reagent packs

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7. Question 7 · Medium

   All of the following are advantages of autoanalysers EXCEPT:

   1. AHigher throughput of samples
   2. BNo need for quality control
   3. CSmaller sample and reagent volumes
   4. DBetter precision of results

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8. Question 8 · Easy

   On a modern autoanalyser, what is the most reliable way to identify each sample tube?

   1. AA handwritten number on the tube
   2. BThe colour of the tube cap
   3. CA barcode label read by the analyser
   4. DThe tube's position in the rack

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9. Question 9 · Medium

   A random-access analyser differs from a batch analyser in that it can:

   1. ARun one test at a time on a batch of samples
   2. BRun without calibration or quality control
   3. CRun any test on any sample in any order
   4. DRun tests without using any reagents

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10. Question 10 · Medium

    In total laboratory automation, the pre-analytical module mainly:

    1. APlots Levey-Jennings charts for QC
    2. BSorts, centrifuges, decaps and aliquots tubes
    3. CStores tested tubes for later retesting
    4. DValidates results against reference ranges

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11. Question 11 · Medium

    An 'open' autoanalyser system differs from a 'closed' one in that it:

    1. ANeeds no calibration before use
    2. BAccepts reagents from any manufacturer
    3. CRuns only one test on each sample
    4. DHas no cover over its sample tray

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12. Question 12 · Medium

    Dry-chemistry analysers use reagents dried in layers on a slide. Where does the water for the reaction come from?

    1. AA diluent added by the probe
    2. BThe patient's sample itself
    3. CHumid air in the incubator
    4. DDeionised water in each pack

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13. Question 13 · Easy

    The ion-selective electrode (ISE) unit of an autoanalyser measures:

    1. ATotal protein and albumin
    2. BGlucose, urea and creatinine
    3. CSodium, potassium and chloride
    4. DALT, AST and ALP

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14. Question 14 · Easy

    An analyser in which sample and reagent are spun into cuvettes on a rotor, each read as it passes the light beam, is a:

    1. ACentrifugal analyser
    2. BSemi-autoanalyser
    3. CContinuous-flow analyser
    4. DDry-chemistry analyser

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15. Question 15 · Medium

    On an autoanalyser, a sample with ALT 3,000 U/L is followed by one reading 95 U/L. After a probe wash the second sample gives 30 U/L. What caused its first result?

    1. AReagent deterioration
    2. BShort sampling
    3. CSample carryover
    4. DCalibration drift

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16. Question 16 · Easy

    Which analyser feature detects the surface of the sample, so that the probe dips only slightly into it?

    1. AAuto-dilution
    2. BDelta checking
    3. CLiquid-level sensing
    4. DClot detection

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17. Question 17 · Medium

    An LIS rule that automatically adds a free T4 test when the TSH result is abnormal is an example of:

    1. ABatch testing
    2. BAutoverification
    3. CDelta checking
    4. DReflex testing

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18. Question 18 · Easy

    Testing done at or near the patient, such as blood glucose with a glucometer in the ward, is called:

    1. AReference laboratory testing
    2. BTotal laboratory automation
    3. CBatch analysis
    4. DPoint-of-care testing

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19. Question 19 · Hard

    An ALT result is reported as 160 U/L with a 'substrate depletion' flag; the starting absorbance at 340 nm was already very low. QC is within limits. What should be done?

    1. AReport 160 U/L as it stands
    2. BRerun with double sample volume
    3. CDilute the sample and rerun it
    4. DRecalibrate the ALT assay

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20. Question 20 · Hard

    On an autoanalyser, every photometric test on all samples and both QC levels shows low light or absorbance error flags, while sodium and potassium by ISE are normal. What is the most likely fault?

    1. AExpired calibrator lot
    2. BWorn ISE reference electrode
    3. CFaulty barcode reader
    4. DAgeing photometer lamp

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21. Question 21 · Medium

    In a laboratory information system, autoverification means that:

    1. AResults meeting set rules release without manual review
    2. BEvery result is checked by a pathologist before release
    3. CThe analyser sends orders back to the ward
    4. DResults are released before QC is run

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22. Question 22 · Hard

    Serum alkaline phosphatase is run in kinetic mode at 405 nm with a factor of 2757. Readings taken a minute apart are 0.400, 0.430, 0.460 and 0.490. Which result should be reported?

    1. A83 U/L
    2. B28 U/L
    3. C1,351 U/L
    4. D248 U/L

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23. Question 23 · Easy

    Which light source is most commonly used in the photometer of a clinical chemistry autoanalyser?

    1. AMercury vapour lamp
    2. BTungsten-halogen lamp
    3. CSodium vapour lamp
    4. DHollow cathode lamp

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24. Question 24 · Easy

    The number of tests an autoanalyser can complete in one hour is called its:

    1. ADwell time
    2. BCarryover
    3. CTurnaround time
    4. DThroughput

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25. Question 25 · Medium

    What is the main safety advantage of cap-piercing (closed-tube) sampling on an analyser?

    1. AIt doubles the analyser's throughput
    2. BIt allows clotted samples to be tested
    3. CIt removes the need for sample barcodes
    4. DIt avoids aerosols from opening tubes

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