Master Laboratory Operations for your laboratory certification exam with our comprehensive collection of 63 multiple-choice questions (MCQs). Focused exclusively on Manual/Automated Methodology and Instrumentation , these practice questions align with the latest syllabi of ASCP MLS, AMT MLT/MT, AIMS, CSMLS, IBMS, HAAD/DOH, DHA, and MOH exams. Each MCQ includes detailed explanations and references to reinforce key concepts. Sharpen your critical thinking, identify knowledge gaps, and build speed with exam-style questions—all for free. Ideal for targeted revision!
63 MCQs (202-264):
- What is the most common configuration of modern automated analyzers?
a) Batch processing systems
b) Random access analyzers
c) Sequential testing modules
d) Manual loading platforms - The primary benefit of barcode labeling in laboratory automation is:
a) Reduced specimen identification errors
b) Faster centrifugation
c) Lower reagent costs
d) Smaller sample volumes - The Analytical Measurement Range (AMR) represents:
a) The test values measurable without dilution
b) The instrument’s warranty period
c) Quality control acceptance limits
d) Manufacturer recommended maintenance schedule - Standard microscope eyepieces typically provide what magnification?
a) 5x
b) 10x
c) 40x
d) 100x - To properly adjust microscope light intensity, you should modify the:
a) Condenser height
b) Rheostat setting
c) Objective lens
d) Stage controls - Phase contrast microscopy is particularly valuable for:
a) Viewing stained slides
b) Observing unstained specimens
c) Measuring cell counts
d) Performing chemical analysis - Köhler illumination ensures optimal:
a) Magnification
b) Contrast and resolution
c) Color reproduction
d) Specimen heating - Microscope immersion oil should be:
a) Left on lenses between uses
b) Cleaned after each use
c) Only used with 40x objectives
d) Stored in refrigeration - A black ring on a microscope objective indicates:
a) Low power magnification
b) Oil immersion requirement
c) Damaged lens
d) Specialized staining capability - The most critical factor for safe centrifuge operation is:
a) Timer setting
b) Proper balancing
c) Tube material
d) Rotation direction - A centrifuge with 30cm radius spinning at 3000 RPM generates approximately:
a) 900 G-force
b) 3,000 G-force
c) 9,000 G-force
d) 30,000 G-force
- Centrifuge speed should be monitored using a:
a) Tachometer
b) Thermometer
c) Voltmeter
d) Barometer - Cobalt chloride desiccant indicates moisture absorption by turning:
a) Blue to pink
b) Clear to white
c) Green to yellow
d) Red to black - Blood gas analyzers typically measure pH using:
a) Potentiometry
b) Spectrophotometry
c) Conductometry
d) Fluorometry - Absorbance (A) and transmittance (T) are related by which equation?
a) A = 1 – log(T)
b) A = 2 + log(T)
c) A = 2 – log(T)
d) A = 1 + log(T) - To calculate an unknown concentration using Beer’s Law:
a) Multiply standard absorbance by unknown concentration
b) Compare absorbance ratios of standard and unknown
c) Average multiple standard readings
d) Subtract blank absorbance from all readings - Atomic absorption spectrophotometry measures:
a) Light emission from excited atoms
b) Energy absorbed by ground state atoms
c) Molecular vibration frequencies
d) Electrical conductivity of solutions - The ultraviolet wavelength range includes:
a) 340 nm
b) 450 nm
c) 540 nm
d) 650 nm - A didymium filter is primarily used to:
a) Measure fluorescence intensity
b) Verify spectrophotometer wavelength calibration
c) Filter bacterial contaminants
d) Adjust light path length - The component that isolates specific wavelengths in a spectrophotometer is called the:
a) Photodetector
b) Monochromator
c) Cuvette
d) Diffraction plate - When preparing a spectrophotometer for analysis, the first step should be:
a) Insert the sample cuvette
b) Select the appropriate wavelength
c) Zero with blank solution
d) Run quality control - Dual-beam photometry compensates for variations in:
a) Sample viscosity
b) Light source intensity
c) Cuvette diameter
d) Ambient temperature - Atomic absorption instruments use which specialized light source?
a) Tungsten-halogen lamp
b) Hollow cathode lamp
c) Deuterium arc lamp
d) Light-emitting diode - The spectral purity of a spectrophotometer is indicated by its:
a) Photomultiplier sensitivity
b) Absorbance range
c) Bandwidth specification
d) Digital resolution - Bichromatic analysis measures absorbance at:
a) Two wavelengths simultaneously
b) Alternating wavelengths
c) Multiple time points
d) Different temperatures - When establishing a new spectrophotometric method, the first analytical step is to determine:
a) Optimal wavelength for maximum absorbance
b) Required sample volume
c) Appropriate cuvette material
d) Reagent stability - The fundamental principle of chromatography is:
a) Differential solubility partitioning
b) Electrical charge separation
c) Magnetic property variation
d) Thermal conductivity differences - Gel filtration chromatography separates molecules based on:
a) Polarity differences
b) Molecular size
c) Ionic charge
d) Fluorescence properties - In HPLC, backpressure exceeding normal limits typically indicates:
a) Column obstruction
b) Insufficient mobile phase
c) Detector saturation
d) Sample evaporation - Gas chromatography requires analytes to be:
a) Volatile or derivatized to volatility
b) Fluorescently tagged
c) Dissolved in water
d) Electrically charged - Thin-layer chromatography Rf values represent:
a) Solute migration relative to solvent front
b) Time to complete separation
c) Temperature stability range
d) Adsorbent particle size
- Ion-exchange chromatography separates molecules based on:
a) Net surface charge
b) Hydrophobicity
c) Molecular weight
d) Light absorption - Steric exclusion chromatography is most effective for separating:
a) Small molecules from large ones
b) Charged from uncharged particles
c) Hydrophobic compounds
d) Metal ions - Reverse-phase HPLC uses:
a) Nonpolar stationary phase
b) Cationic resins
c) Aqueous mobile phases only
d) High-temperature columns - The primary function of the guard column in HPLC is to:
a) Protect main column from contaminants
b) Increase flow rate
c) Reduce backpressure
d) Enhance detection sensitivity - In gas chromatography, retention time is affected by:
a) Column temperature
b) Detector wavelength
c) Sample color
d) Mobile phase pH - Affinity chromatography exploits:
a) Biological binding specificity
b) Molecular weight differences
c) Electrical charge gradients
d) Solubility in organic solvents - In electrophoresis, buffer solutions primarily serve to:
a) Maintain pH and conduct current
b) Increase sample viscosity
c) Visualize separated components
d) Prevent protein denaturation - Distorted protein bands in electrophoresis most commonly result from:
a) Excessive sample concentration
b) Low buffer ionic strength
c) Short run time
d) High voltage settings - The retention factor (Rf) in thin-layer chromatography represents:
a) Solute migration distance relative to solvent front
b) Time required for complete separation
c) Temperature stability of compounds
d) Adsorbent material porosity - High pressure liquid chromatography (HPLC) systems showing sudden pressure increases likely indicate:
a) Column blockage
b) Mobile phase depletion
c) Detector malfunction
d) Sample evaporation - Gas chromatography requires analytes to be:
a) Thermally stable and volatile
b) Fluorescently labeled
c) Dissolved in aqueous solution
d) Magnetically active - Ion-selective electrode specificity is determined by:
a) Membrane composition
b) Reference electrode material
c) Sample volume
d) Voltage amplitude - Fluorometers detect emitted light at which angle to the excitation source?
a) 180°
b) 90°
c) 45°
d) 360° - The key advantage of fluorescence detection over absorbance is:
a) Higher sensitivity
b) Wider linear range
c) Less affected by temperature
d) No need for wavelength selection - Nephelometry is most commonly used to measure:
a) Antigen-antibody complexes
b) DNA concentration
c) Electrolyte levels
d) Enzyme activity - In flow cytometry, forward scatter correlates with:
a) Cell size
b) Cytoplasmic granularity
c) Surface markers
d) DNA content - Side scatter in flow cytometry provides information about:
a) Cellular internal complexity
b) Membrane potential
c) Total protein content
d) Mitochondrial activity - Fluorometers measure:
a) Light emission at longer wavelengths than excitation
b) Electrical conductivity changes
c) Radioactive decay
d) Thermal energy release - Nephelometry detects:
a) Light scattered at 90° angles
b) Complete light absorption
c) Electrical impedance
d) Magnetic susceptibility - Flow cytometry identifies cells using:
a) Fluorescent-labeled antibodies
b) X-ray diffraction
c) Ultrasonic waves
d) Infrared spectroscopy - In molecular diagnostics, an OD260 reading of 1.0 corresponds to:
a) 10 μg/mL DNA concentration
b) 20 μg/mL DNA concentration
c) 50 μg/mL DNA concentration
d) 100 μg/mL DNA concentration - Real-time PCR quantification relies on:
a) Cycle threshold (Ct) values
b) Electrophoretic mobility
c) Temperature gradients
d) pH changes - Pulsed-field gel electrophoresis is particularly useful for:
a) Bacterial strain typing
b) Protein quantification
c) Small RNA separation
d) Lipid analysis - Automated hematology analyzers calculate hematocrit using:
a) Direct centrifugation
b) MCV × RBC count
c) Hemoglobin concentration
d) Plasma protein levels - The Coulter principle measures cells by detecting:
a) Light scatter
b) Electrical impedance
c) Fluorescence intensity
d) Magnetic resonance - When an automated platelet count is abnormally low, the next step should be:
a) Report immediately
b) Request new sample
c) Verify by blood smear review
d) Repeat with higher dilution - Electrical impedance cell counting requires:
a) Fluorescent labels
b) Conductive diluent
c) High-speed centrifugation
d) Stained preparations - If a hematology analyzer control shows abnormal MCV, first:
a) Adjust the calibration
b) Repeat the control
c) Shut down the instrument
d) Change reagents - When evaluating a hematology analyzer’s linearity, the most appropriate action for out-of-range results is:
a) Automatically dilute all samples
b) Verify with manual methods
c) Adjust the calibration curve
d) Repeat with new reagents - An elevated basophil count on automated analysis should first be:
a) Reported immediately
b) Confirmed by peripheral smear
c) Repeated with warmer reagents
d) Correlated with IgE levels - The primary advantage of optical platelet counting over impedance methods is:
a) Better detection of giant platelets
b) Faster analysis time
c) Lower reagent cost
d) Smaller sample volume - When a hematology analyzer flags “NRBC” (nucleated red blood cells), the most appropriate next step is:
a) Report the automated count directly
b) Perform manual differential count
c) Warm the sample to 37°C and re-run
d) Centrifuge and test plasma only
Answer Key
Answer Key:
- b) Random access analyzers
- a) Reduced specimen identification errors
- a) The test values measurable without dilution
- b) 10x
- b) Rheostat setting
- b) Observing unstained specimens
- b) Contrast and resolution
- b) Cleaned after each use
- b) Oil immersion requirement
- b) Proper balancing
- b) 3,000 G-force
- a) Tachometer
- a) Blue to pink
- a) Potentiometry
- c) A = 2 – log(T)
- b) Compare absorbance ratios of standard and unknown
- b) Energy absorbed by ground state atoms
- a) 340 nm
- b) Verify spectrophotometer wavelength calibration
- b) Monochromator
- b) Select the appropriate wavelength
- b) Light source intensity
- b) Hollow cathode lamp
- c) Bandwidth specification
- a) Two wavelengths simultaneously
- a) Optimal wavelength for maximum absorbance
- a) Differential solubility partitioning
- b) Molecular size
- a) Column obstruction
- a) Volatile or derivatized to volatility
- a) Solute migration relative to solvent front
- a) Net surface charge
- a) Small molecules from large ones
- a) Nonpolar stationary phase
- a) Protect main column from contaminants
- a) Column temperature
- a) Biological binding specificity
- a) Maintain pH and conduct current
- a) Excessive sample concentration
- a) Solute migration distance relative to solvent front
- a) Column blockage
- a) Thermally stable and volatile
- a) Membrane composition
- b) 90°
- a) Higher sensitivity
- a) Antigen-antibody complexes
- a) Cell size
- a) Cellular internal complexity
- a) Light emission at longer wavelengths than excitation
- a) Light scattered at 90° angles
- a) Fluorescent-labeled antibodies
- c) 50 μg/mL DNA concentration
- a) Cycle threshold (Ct) values
- a) Bacterial strain typing
- b) MCV × RBC count
- b) Electrical impedance
- c) Verify by blood smear review
- b) Conductive diluent
- b) Repeat the control
- b) Verify with manual methods
- b) Confirmed by peripheral smear
- a) Better detection of giant platelets
- b) Perform manual differential count
Top 8 Medical Laboratory Scientist (MLS) Exams:
Top 8 Medical Laboratory Scientist (MLS) Exams that are recognized globally and can help professionals validate their credentials and enhance their career opportunities:
1. ASCP – American Society for Clinical Pathology (USA)
- Exam Name: MLS(ASCP)
- Eligibility: Bachelor’s degree with clinical laboratory experience.
- Global Recognition: High
- Purpose: Certifies Medical Laboratory Scientists in the United States and internationally.
2. AMT – American Medical Technologists (USA)
- Exam Name: MLT(AMT) or MT(AMT)
- Eligibility: Academic and/or work experience in medical laboratory technology.
- Global Recognition: Moderate
- Purpose: Credentialing for medical technologists and technicians.
3. AIMS – Australian Institute of Medical and Clinical Scientists
- Exam Name: AIMS Certification Exam
- Eligibility: Assessment of qualifications and work experience.
- Recognition: Required for practice in Australia.
- Purpose: Certification and registration in Australia.
4. CSMLS – Canadian Society for Medical Laboratory Science
- Exam Name: CSMLS General or Subject-specific Exams
- Eligibility: Graduation from a CSMLS-accredited program or equivalent.
- Recognition: Canada
- Purpose: Entry-to-practice certification in Canada.
5. IBMS – Institute of Biomedical Science (UK)
- Exam Name: Registration and Specialist Portfolio Assessment
- Eligibility: Accredited degree and lab experience.
- Recognition: UK and some Commonwealth countries.
- Purpose: Biomedical Scientist registration with the HCPC (UK).
6. HAAD / DOH – Department of Health, Abu Dhabi (UAE)
- Exam Name: DOH/HAAD License Exam
- Eligibility: Degree in medical laboratory science and experience.
- Recognition: UAE (Abu Dhabi)
- Purpose: Licensure for medical laboratory practice in Abu Dhabi.
7. DHA – Dubai Health Authority (UAE)
- Exam Name: DHA License Exam for Medical Laboratory Technologists
- Eligibility: Relevant degree and experience.
- Recognition: Dubai, UAE
- Purpose: Professional license for clinical laboratory practice in Dubai.
8. MOH – Ministry of Health (Gulf Countries like UAE, Saudi Arabia, Kuwait)
- Exam Name: MOH License Exam
- Eligibility: BSc/Diploma in Medical Laboratory + experience.
- Recognition: Varies by country.
- Purpose: Required for practicing in public and private sector labs.
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