AMT MLS EXAM 2025/2026 | 250 ORIGINAL EXAM-STYLE
QUESTIONS + CORRECT ANSWERS & DETAILED
RATIONALES
I. GENERAL LABORATORY
1. A serum specimen is visibly hemolyzed. Which analyte is most likely to show a clinically significant spurious
increase?
Image: Public-domain laboratory photograph; used as visual orientation.
Potassium
Sodium
Chloride
Bicarbonate
Correct answer: Potassium
Red-cell rupture releases intracellular potassium into serum. Hemolysis can therefore falsely increase potassium, as well as LD and AST in
many methods.
2. Which Westgard rule is commonly used to identify a systematic error when two consecutive control results exceed
the same control limit on the same side of the mean?
1■s
2■s
R■s
10x
Correct answer: 2■s
The 2■s rule is triggered when two consecutive control measurements exceed the same ±2 SD limit, suggesting systematic error.
3. A glucose specimen cannot be analyzed for several hours. Which action best preserves the glucose concentration?
Leave whole blood at room temperature
Separate serum/plasma from cells promptly
Add distilled water
Expose the tube to light
Correct answer: Separate serum/plasma from cells promptly
Cells continue glycolysis after collection. Prompt separation reduces cellular glucose consumption; appropriate glycolysis inhibitors may
also be used when indicated.
4. Which quality-control concept describes how close repeated measurements are to one another?
Accuracy
Precision
Sensitivity
Specificity
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 1
, Correct answer: Precision
Precision describes reproducibility or closeness of repeated measurements; accuracy describes closeness to the true value.
5. A pipette repeatedly delivers 98 µL when set to 100 µL. This primarily represents:
Random error
Systematic error
Carryover
Clerical error
Correct answer: Systematic error
A consistent bias in one direction is systematic error. Calibration or pipette maintenance should be investigated.
6. Which tube additive is used for routine coagulation testing?
EDTA
Sodium citrate
Heparin
Sodium fluoride
Correct answer: Sodium citrate
Light-blue sodium citrate tubes bind calcium reversibly and are used for PT, aPTT and many coagulation assays.
7. What is the principal purpose of a Safety Data Sheet (SDS)?
To report patient results
To provide hazard, handling and emergency information for chemicals
To replace competency records
To document instrument calibration only
Correct answer: To provide hazard, handling and emergency information for chemicals
An SDS communicates chemical hazards, safe handling, storage, exposure control and emergency measures.
8. A mislabeled patient tube is discovered before testing. What is the best action?
Image: Blood smear image; public educational Wikimedia Commons image.
Correct the label yourself
Test it if the requisition is clear
Follow the laboratory's specimen-rejection and recollection procedure
Ask another technologist to guess the identity
Correct answer: Follow the laboratory's specimen-rejection and recollection procedure
Patient identification is critical. A mislabeled specimen should be handled according to the laboratory's established rejection/recollection
policy rather than relabeled by assumption.
9. Which statistic is most useful for comparing the spread of results between assays with different means?
Range
Coefficient of variation
Median
Mode
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 2
, Correct answer: Coefficient of variation
CV = SD/mean × 100 and expresses imprecision relative to the mean, allowing comparison across assays with different scales.
10. A photometric assay's absorbance is above the instrument's reportable range. What is the best next step?
Report the value as zero
Dilute the specimen according to the validated procedure and repeat
Change the patient's diagnosis
Ignore the result
Correct answer: Dilute the specimen according to the validated procedure and repeat
A validated dilution brings the analyte into the analytical measurement range, after which the dilution factor is applied.
11. Which preanalytical error is most associated with a falsely increased potassium result?
Icterus
Hemolysis
Lipemia
Delayed urine refrigeration
Correct answer: Hemolysis
Hemolysis releases intracellular potassium from erythrocytes.
12. A specimen collected in EDTA is accidentally submitted for calcium measurement. What is the likely effect?
Falsely increased calcium
Falsely decreased calcium
No effect
Falsely increased sodium
Correct answer: Falsely decreased calcium
EDTA chelates divalent cations such as calcium and can markedly lower measured calcium.
13. Which order of draw places blood culture bottles before citrate, serum, heparin and EDTA tubes?
Correct order
EDTA first
Serum first
Fluoride first
Correct answer: Correct order
Blood cultures are collected first to reduce contamination from additives in subsequent tubes. The exact institutional sequence should be
followed.
14. What is the main reason to avoid prolonged tourniquet application during venipuncture?
It sterilizes the site
It can cause hemoconcentration and alter analyte concentrations
It prevents clotting
It increases specimen volume
Correct answer: It can cause hemoconcentration and alter analyte concentrations
Prolonged venous stasis can concentrate proteins and cellular components and alter some chemistry results.
15. A chemistry analyzer produces a steady upward drift in control values over several runs. This pattern is best
described as:
Shift
Trend
Random scatter
No error
Correct answer: Trend
A trend is a gradual movement of control values in one direction over time and may indicate reagent deterioration or instrument change.
16. Which analytical characteristic is the ability to detect small quantities of an analyte?
Specificity
Sensitivity
Precision
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 3
, Linearity
Correct answer: Sensitivity
Analytical sensitivity relates to the ability to detect low concentrations or small changes in concentration.
17. Which control material should be treated like a patient specimen during routine analysis?
Quality-control material
Distilled water
Cleaning solution
Calibration blank only
Correct answer: Quality-control material
Quality-control materials are processed through the analytical system to monitor performance before patient results are accepted.
18. A centrifuge begins vibrating excessively during operation. What is the safest immediate response?
Increase the speed
Stop the centrifuge and inspect for imbalance or mechanical problems
Open the lid while spinning
Add another tube without stopping
Correct answer: Stop the centrifuge and inspect for imbalance or mechanical problems
Excess vibration can indicate an imbalance or equipment fault. Stop safely and investigate according to laboratory procedure.
19. Which laboratory practice best reduces aerosol exposure when opening a tube that may contain infectious
material?
Open it rapidly near the face
Use appropriate containment such as a biological safety cabinet when indicated
Blow across the tube
Remove the cap with bare hands
Correct answer: Use appropriate containment such as a biological safety cabinet when indicated
A biological safety cabinet and appropriate PPE help protect personnel from infectious aerosols when procedures have aerosol-generating
potential.
20. Which disinfectant is commonly used for routine decontamination of many laboratory surfaces when compatible
with the material?
Appropriately prepared sodium hypochlorite solution
Distilled water only
Mineral oil
Sucrose solution
Correct answer: Appropriately prepared sodium hypochlorite solution
Sodium hypochlorite is widely used for disinfection, with concentration and contact time determined by the laboratory protocol and organism
risk.
21. A laboratory's proficiency-testing result is unacceptable. What should happen next?
Discard the report
Investigate the cause, document corrective action and assess patient impact
Immediately change all instruments
Ignore it if controls were acceptable
Correct answer: Investigate the cause, document corrective action and assess patient impact
An unacceptable PT event requires documented investigation and corrective action, including consideration of whether patient results were
affected.
22. Which term describes a test's ability to correctly identify individuals who do NOT have the disease?
Sensitivity
Specificity
Precision
Bias
Correct answer: Specificity
Specificity is the proportion of true negatives among those without the disease.
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 4
QUESTIONS + CORRECT ANSWERS & DETAILED
RATIONALES
I. GENERAL LABORATORY
1. A serum specimen is visibly hemolyzed. Which analyte is most likely to show a clinically significant spurious
increase?
Image: Public-domain laboratory photograph; used as visual orientation.
Potassium
Sodium
Chloride
Bicarbonate
Correct answer: Potassium
Red-cell rupture releases intracellular potassium into serum. Hemolysis can therefore falsely increase potassium, as well as LD and AST in
many methods.
2. Which Westgard rule is commonly used to identify a systematic error when two consecutive control results exceed
the same control limit on the same side of the mean?
1■s
2■s
R■s
10x
Correct answer: 2■s
The 2■s rule is triggered when two consecutive control measurements exceed the same ±2 SD limit, suggesting systematic error.
3. A glucose specimen cannot be analyzed for several hours. Which action best preserves the glucose concentration?
Leave whole blood at room temperature
Separate serum/plasma from cells promptly
Add distilled water
Expose the tube to light
Correct answer: Separate serum/plasma from cells promptly
Cells continue glycolysis after collection. Prompt separation reduces cellular glucose consumption; appropriate glycolysis inhibitors may
also be used when indicated.
4. Which quality-control concept describes how close repeated measurements are to one another?
Accuracy
Precision
Sensitivity
Specificity
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 1
, Correct answer: Precision
Precision describes reproducibility or closeness of repeated measurements; accuracy describes closeness to the true value.
5. A pipette repeatedly delivers 98 µL when set to 100 µL. This primarily represents:
Random error
Systematic error
Carryover
Clerical error
Correct answer: Systematic error
A consistent bias in one direction is systematic error. Calibration or pipette maintenance should be investigated.
6. Which tube additive is used for routine coagulation testing?
EDTA
Sodium citrate
Heparin
Sodium fluoride
Correct answer: Sodium citrate
Light-blue sodium citrate tubes bind calcium reversibly and are used for PT, aPTT and many coagulation assays.
7. What is the principal purpose of a Safety Data Sheet (SDS)?
To report patient results
To provide hazard, handling and emergency information for chemicals
To replace competency records
To document instrument calibration only
Correct answer: To provide hazard, handling and emergency information for chemicals
An SDS communicates chemical hazards, safe handling, storage, exposure control and emergency measures.
8. A mislabeled patient tube is discovered before testing. What is the best action?
Image: Blood smear image; public educational Wikimedia Commons image.
Correct the label yourself
Test it if the requisition is clear
Follow the laboratory's specimen-rejection and recollection procedure
Ask another technologist to guess the identity
Correct answer: Follow the laboratory's specimen-rejection and recollection procedure
Patient identification is critical. A mislabeled specimen should be handled according to the laboratory's established rejection/recollection
policy rather than relabeled by assumption.
9. Which statistic is most useful for comparing the spread of results between assays with different means?
Range
Coefficient of variation
Median
Mode
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 2
, Correct answer: Coefficient of variation
CV = SD/mean × 100 and expresses imprecision relative to the mean, allowing comparison across assays with different scales.
10. A photometric assay's absorbance is above the instrument's reportable range. What is the best next step?
Report the value as zero
Dilute the specimen according to the validated procedure and repeat
Change the patient's diagnosis
Ignore the result
Correct answer: Dilute the specimen according to the validated procedure and repeat
A validated dilution brings the analyte into the analytical measurement range, after which the dilution factor is applied.
11. Which preanalytical error is most associated with a falsely increased potassium result?
Icterus
Hemolysis
Lipemia
Delayed urine refrigeration
Correct answer: Hemolysis
Hemolysis releases intracellular potassium from erythrocytes.
12. A specimen collected in EDTA is accidentally submitted for calcium measurement. What is the likely effect?
Falsely increased calcium
Falsely decreased calcium
No effect
Falsely increased sodium
Correct answer: Falsely decreased calcium
EDTA chelates divalent cations such as calcium and can markedly lower measured calcium.
13. Which order of draw places blood culture bottles before citrate, serum, heparin and EDTA tubes?
Correct order
EDTA first
Serum first
Fluoride first
Correct answer: Correct order
Blood cultures are collected first to reduce contamination from additives in subsequent tubes. The exact institutional sequence should be
followed.
14. What is the main reason to avoid prolonged tourniquet application during venipuncture?
It sterilizes the site
It can cause hemoconcentration and alter analyte concentrations
It prevents clotting
It increases specimen volume
Correct answer: It can cause hemoconcentration and alter analyte concentrations
Prolonged venous stasis can concentrate proteins and cellular components and alter some chemistry results.
15. A chemistry analyzer produces a steady upward drift in control values over several runs. This pattern is best
described as:
Shift
Trend
Random scatter
No error
Correct answer: Trend
A trend is a gradual movement of control values in one direction over time and may indicate reagent deterioration or instrument change.
16. Which analytical characteristic is the ability to detect small quantities of an analyte?
Specificity
Sensitivity
Precision
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 3
, Linearity
Correct answer: Sensitivity
Analytical sensitivity relates to the ability to detect low concentrations or small changes in concentration.
17. Which control material should be treated like a patient specimen during routine analysis?
Quality-control material
Distilled water
Cleaning solution
Calibration blank only
Correct answer: Quality-control material
Quality-control materials are processed through the analytical system to monitor performance before patient results are accepted.
18. A centrifuge begins vibrating excessively during operation. What is the safest immediate response?
Increase the speed
Stop the centrifuge and inspect for imbalance or mechanical problems
Open the lid while spinning
Add another tube without stopping
Correct answer: Stop the centrifuge and inspect for imbalance or mechanical problems
Excess vibration can indicate an imbalance or equipment fault. Stop safely and investigate according to laboratory procedure.
19. Which laboratory practice best reduces aerosol exposure when opening a tube that may contain infectious
material?
Open it rapidly near the face
Use appropriate containment such as a biological safety cabinet when indicated
Blow across the tube
Remove the cap with bare hands
Correct answer: Use appropriate containment such as a biological safety cabinet when indicated
A biological safety cabinet and appropriate PPE help protect personnel from infectious aerosols when procedures have aerosol-generating
potential.
20. Which disinfectant is commonly used for routine decontamination of many laboratory surfaces when compatible
with the material?
Appropriately prepared sodium hypochlorite solution
Distilled water only
Mineral oil
Sucrose solution
Correct answer: Appropriately prepared sodium hypochlorite solution
Sodium hypochlorite is widely used for disinfection, with concentration and contact time determined by the laboratory protocol and organism
risk.
21. A laboratory's proficiency-testing result is unacceptable. What should happen next?
Discard the report
Investigate the cause, document corrective action and assess patient impact
Immediately change all instruments
Ignore it if controls were acceptable
Correct answer: Investigate the cause, document corrective action and assess patient impact
An unacceptable PT event requires documented investigation and corrective action, including consideration of whether patient results were
affected.
22. Which term describes a test's ability to correctly identify individuals who do NOT have the disease?
Sensitivity
Specificity
Precision
Bias
Correct answer: Specificity
Specificity is the proportion of true negatives among those without the disease.
Original MLS exam-style practice bank — not actual/leaked AMT exam content. Page 4
