ESTUDYR
MT(AAB) BASIC KNOWLEDGE PRACTICE QUESTIONS: PRACTICE
FOR THE MT(AAB) BASIC KNOWLEDGE EXAM 1
The monitoring of laboratory processes to ensure consistent, accurate test results is best
described as:
a) Corporate compliance
b) Critical thinking
c) Quality assurance
d) Risk management
Rationale: Quality assurance (QA) is the system of planned activities and policies that ensure
test processes and results meet established standards across pre-analytic, analytic, and post-
analytic phases.
Which QC rule indicates a random error when a single control value exceeds ±2 standard
deviations from the mean?
a) 1-3s rule
b) 1-2s rule
c) 2-2s rule
d) 1-3s rule
Rationale: The 1-3s rule is triggered when a single control exceeds ±3 SD, indicating a probable
gross error; however many labs use 1-2s as warning and 1-3s as rejection. (Note: Basic
Knowledge level emphasizes understanding of 1-2s/1-3s concepts.)
A laboratory uses Westgard rules for QC. Which rule is violated when two consecutive
control measurements exceed +2 SD on the same side of the mean?
a) 1-2s
b) 2-2s
c) R-4s
d) 4-1s
Rationale: The 2-2s rule flags systematic error when two consecutive controls are beyond ±2 SD
on the same side of the mean.
An instrument calibration establishes the relationship between instrument signal and
analyte concentration. Which statement is true?
a) Calibration checks precision only.
b) Calibration is unnecessary if QC passes.
c) Calibration ensures accuracy by defining instrument response across concentrations.
d) Calibration corrects for patient specimen variation.
, ESTUDYR
Rationale: Calibration defines how instrument signals convert to concentrations, directly
affecting accuracy; QC monitors ongoing performance.
Which is a pre-analytical source of error?
a) Instrument drift
b) Incorrect reagent lot
c) Hemolyzed specimen due to traumatic venipuncture
d) Improper QC rule selection
Rationale: Pre-analytical errors occur before analysis (collection, transport); hemolysis from
poor draw technique alters analytes (e.g., K+, LDH).
Precision is best defined as:
a) Closeness to the true value
b) Reproducibility of repeated measurements
c) Systematic deviation from the target
d) The mean of replicate values
Rationale: Precision refers to how consistently repeated measurements agree (low random
error); accuracy refers to closeness to true value.
A control material has mean = 100 units and SD = 2. A control result of 106 units would be
approximately how many SDs from the mean?
a) 2 SD
b) 3 SD
c) 3 SD
d) 0.5 SD
Rationale: (106−100)=6; 6/2=3 SD. A 3 SD deviation typically triggers rejection under many QC
rules.
Which term describes the ability of a test to correctly identify those without the disease?
a) Sensitivity
b) Specificity
c) Predictive value positive
d) Prevalence
Rationale: Specificity = true negatives / (true negatives + false positives); it measures correct
identification of disease absence.
A lab receives a proficiency testing (PT) sample and reports results. PT performance is used
primarily to evaluate:
a) Individual patient care decisions
b) Daily QC only
MT(AAB) BASIC KNOWLEDGE PRACTICE QUESTIONS: PRACTICE
FOR THE MT(AAB) BASIC KNOWLEDGE EXAM 1
The monitoring of laboratory processes to ensure consistent, accurate test results is best
described as:
a) Corporate compliance
b) Critical thinking
c) Quality assurance
d) Risk management
Rationale: Quality assurance (QA) is the system of planned activities and policies that ensure
test processes and results meet established standards across pre-analytic, analytic, and post-
analytic phases.
Which QC rule indicates a random error when a single control value exceeds ±2 standard
deviations from the mean?
a) 1-3s rule
b) 1-2s rule
c) 2-2s rule
d) 1-3s rule
Rationale: The 1-3s rule is triggered when a single control exceeds ±3 SD, indicating a probable
gross error; however many labs use 1-2s as warning and 1-3s as rejection. (Note: Basic
Knowledge level emphasizes understanding of 1-2s/1-3s concepts.)
A laboratory uses Westgard rules for QC. Which rule is violated when two consecutive
control measurements exceed +2 SD on the same side of the mean?
a) 1-2s
b) 2-2s
c) R-4s
d) 4-1s
Rationale: The 2-2s rule flags systematic error when two consecutive controls are beyond ±2 SD
on the same side of the mean.
An instrument calibration establishes the relationship between instrument signal and
analyte concentration. Which statement is true?
a) Calibration checks precision only.
b) Calibration is unnecessary if QC passes.
c) Calibration ensures accuracy by defining instrument response across concentrations.
d) Calibration corrects for patient specimen variation.
, ESTUDYR
Rationale: Calibration defines how instrument signals convert to concentrations, directly
affecting accuracy; QC monitors ongoing performance.
Which is a pre-analytical source of error?
a) Instrument drift
b) Incorrect reagent lot
c) Hemolyzed specimen due to traumatic venipuncture
d) Improper QC rule selection
Rationale: Pre-analytical errors occur before analysis (collection, transport); hemolysis from
poor draw technique alters analytes (e.g., K+, LDH).
Precision is best defined as:
a) Closeness to the true value
b) Reproducibility of repeated measurements
c) Systematic deviation from the target
d) The mean of replicate values
Rationale: Precision refers to how consistently repeated measurements agree (low random
error); accuracy refers to closeness to true value.
A control material has mean = 100 units and SD = 2. A control result of 106 units would be
approximately how many SDs from the mean?
a) 2 SD
b) 3 SD
c) 3 SD
d) 0.5 SD
Rationale: (106−100)=6; 6/2=3 SD. A 3 SD deviation typically triggers rejection under many QC
rules.
Which term describes the ability of a test to correctly identify those without the disease?
a) Sensitivity
b) Specificity
c) Predictive value positive
d) Prevalence
Rationale: Specificity = true negatives / (true negatives + false positives); it measures correct
identification of disease absence.
A lab receives a proficiency testing (PT) sample and reports results. PT performance is used
primarily to evaluate:
a) Individual patient care decisions
b) Daily QC only
