Laboratory Quality Control Practice Test

These questions are part of the practice quiz. Start practicing

• Which statement differentiates random error from systematic error?
• Which option is a core element of QC planning for immunoassays?
• What percent of a normal population is encompassed by a reference range defined as Mean ±2SD?
• On a Levey-Jennings plot, dispersion refers to what pattern?
• What is change control, and how does it apply to QC methods or instruments?
• Which term describes the ability to hit the same spot in repeated measurements?
• Variance between the measured and true values.
• Which term describes the factors that affect the measurement of an analyte?
• Which statement about external quality assessment (EQA) is accurate?
• If a lab consistently performs below the group mean in proficiency testing, what action is recommended?
• How would you document a failed instrument downtime that could impact test accuracy?
• How often should internal audits be conducted and what do they typically review?
• Certified Reference Materials (CRMs) are used to...
• Interpret a run where two control measurements are outside the 1-2s rule but within the 4-1s rule.
• Given a control result of 105, an expected mean of 100, and a standard deviation of 4 for the control material, what is the Z-score?
• Why is participation in external quality assessment (EQA) included in QC design?
• If a control mean is 200 and SD is 10, which Z-score corresponds to a result of 180?
• What is the primary objective of Six Sigma?
• When QC results indicate a problem, which action must be documented?
• How is a quality control plan best defined?
• Why are internal QC materials selected with known concentrations near medical decision levels?
• What expresses variability as a percent of the mean?
• Which statement best describes proficiency testing in relation to method comparison?
• Calculate the Z-score for X = 105, μ = 100, σ = 5.
• Which quality control material should simulate real patient specimens and span the clinically important analytical range?
• External quality assessment (EQA) results are used to:
• A preventive maintenance plan for a common laboratory analyzer should include which elements?
• What is the purpose of Westgard rules in laboratory QC?
• Provide an example of a scenario where a single control rule violation is treated differently from multiple consecutive violations.
• What is a key benefit of training and competency assessment in sustaining QC quality?
• Which metric expresses defects per million opportunities in Six Sigma?
• Which plot is used to monitor systematic QC performance across time?
• On a QC chart, which option describes the measurement displayed on the plot?
• In DMAIC, which phase defines the project purpose and scope?
• What is required in method comparison studies to validate a new assay against a reference method?
• Which set of terms correctly represents the '+ attributes' of ALCOA+ data integrity?
• Six Sigma aims to reduce defects to how many defects per million opportunities?
• What are the key components of a control chart?
• What is the purpose of a control chart in QC?
• Why should QC materials span the clinically important analytical range?
• Define CAPA and describe its typical lifecycle in a laboratory quality program.
• What is the purpose of corrective action in QC and how is effectiveness verified?
• Reference Range is typically derived from measurements in which population?
• Which document describes the processes used for testing in a QC program?
• Which statement best defines a nonconforming event vs a corrective action?
• Which statement best describes the 2(2s) Westgard Rule?
• What does cusum indicate when control data are randomly scattered about the expected mean?
• With mean 100 and SD 5, a result of 110 yields Z = 2. Which statement is true?
• Which statistic is the square root of the variance?
• Baseline data in quality improvement refers to which of the following?
• What does a Z-score represent?
• If the control result equals the control mean, the Z-score is
• What is the purpose of external quality assessment (EQA) participation in QC?
• Six Sigma is associated with reducing variation by using how many standard deviations from the mean?
• Traceability in calibration is established by...
• If a control chart displays a point outside the control limits, what is the appropriate action?
• Which action is part of change control when updating QC methods?
• Which Westgard rule requires 10 consecutive control measurements to fall on one side of the mean?
• On a Levey-Jennings Chart, what is the typical acceptable range for control values?
• What constitutes a nonconforming result and how should it be handled?
• Under CLIA QC requirements, how many levels of control materials should be used each day?
• What is also known as Standard Deviation Index or SDI?
• DMAIC stands for Define, Measure, Analyze, Improve, Control.
• A QC plan for a new method should include which items?
• Which statement best describes what a Levey-Jennings plot displays?
• Which ALCOA+ attribute ensures data are contemporaneous?
• The event "One control value exceeds the mean ±3SD" corresponds to which Westgard rule?
• How does proficiency testing influence method comparison and improvement in laboratory QC?
• The Cusum plot is defined as what?
• Progressive drift of reported values from a prior mean is best described as which term?
• Which Westgard rule acts as a warning rule to trigger careful inspection of the following control results?
• What is center line drift on a QC control chart?
• What is a primary purpose of an Analytical Run?
• Which Westgard rule is commonly considered a warning when a single control measurement exceeds the 2 standard deviation limit?
• The 1(3s) Westgard Rule is triggered by:
• Which statement best describes calibration, verification, and validation in a QC program?
• Which term is commonly used interchangeably with Reference Interval?
• Which option correctly states the acronym DMAIC?
• Which statement describes the behavior of a cusum when there is a systematic error?
• Why is data integrity (ALCOA+) critical in QC reporting?
• Which error exists in all measurements and is due to chance?
• How do blank control and negative/positive controls differ in QC?
• Which term describes six consecutive measurements rising or falling and may cross the mean?
• Which factor is not typically considered when designing a QC plan for a new analytical method?
• What measures ensure traceability of reagents and calibrators in QC?
• In a quality control program, how often should calibration procedures be performed?
• Which condition is indicated by six consecutive points on one side of the mean?
• Which statement about the effect of changing the standard deviation on Z-score for a fixed difference is true?
• What does proficiency testing measure?
• What best differentiates calibration traceability from instrument traceability?
• Which guideline is commonly followed in laboratory testing procedures and instrument operation?
• Which statement describes the recommended minimum population size from the local community when establishing a reference range?
• In DMAIC, which phase implements improvements?
• In a quality control program, what constitutes a proper nonconformance investigation following a failed result during downtime?
• In DMAIC, which phase collects baseline data on current processes and identifies problems?
• Which term represents the mathematical average of the data set?
• Which term is the middle value when the data are ordered?
• Which of the following statements describes the Z-score's role in quality control?
• The Waning rule to trigger careful inspection of the following control results corresponds to which Westgard rule?
• Which error is primarily associated with human actions during laboratory testing, such as specimen handling and data entry?
• Which term describes the difference between the measured value and the true value?
• In immunohematology QC records, how long are records retained?
• Which material must be tested in exactly the same manner as patient specimens to ensure proper QC?
• Which statement is true about a Z-score of 3?
• Which type of error can arise from human actions during testing, such as specimen handling and data entry?
• In assay performance, differentiate LOD and LOQ.
• What term describes the ability to achieve accuracy and precision simultaneously?
• Levey-Jennings Charts show the relationship of control limits to which distribution type?
• Which term describes the factors that affect the measurement of an analyte?
• Which term is the value that occurs most frequently?
• PDCA cycle stands for what in QC improvement?
• What does ALCOA+ stand for in data integrity and why is it important in the lab?
• What is a quality indicator (QI) and how is it used in continuous quality improvement?
• Why is recording maintenance activities important for QC?
• After a reagent lot change, which action is appropriate?
• Accuracy in QC, defined as closeness to the true value, is described as which term?
• Westgard Rules measurements per run are generally used with how many control measurements per run?
• Which three items are essential components of a Laboratory Quality Management System (LQMS)?
• Which term labels the concept of testing controls at multiple levels such as Low, Medium, and High?
• How is bias assessed in proficiency testing, and what does it inform?
• During method validation, which term describes the closeness of the mean to the true value?
• Which quality improvement process is aimed at identifying and removing causes of defects?
• Which Westgard rule is described by two consecutive control values where the first exceeds the mean +2SD and the following exceeds the mean −2SD?
• If the difference between result and mean is 6 and the SD is 2, what is the Z-score?
• What distinguishes run acceptance criteria from lot acceptance criteria in QC?
• Which distribution best describes control values in a quality control program?
• What is dispersion of repeated results about the mean?
• In the CAPA lifecycle, which statement best describes the documentation requirement?
• Which Westgard rule is violated when two consecutive control values exceed the mean ±2SD?
• Which statement is true when a Z-score equals 3?
• Which term describes the closeness of repeated results (reproducibility)?
• Levey-Jennings Chart is used to plot which data set?
• Which type of error is related to the organization or design of a laboratory?
• Which statistic is expressed as a percentage and describes variability?
• What is the primary purpose of control materials in QC?
• Pre-analytical factors that can impact QC results include which of the following?
• Which type of error occurs at the interface between a laboratorian and the patient samples?
• Which error influences values consistently in one direction?
• What is the primary reason to retain QC data and maintain audit trails?
• With mean 100 and SD 5, a result of 85 yields Z = -3. Which statement is true?
• Who should have access to QC audit trails?
• What percentage of values lie within 2 standard deviations of the mean in a normal distribution?
• Which term means how close the value is to the true value ( bulls-eye )?
• What term describes the combination of decision criteria used to decide whether an analytical run is in-control or out-of-control?
• Which element is essential for proper sample labeling and chain of custody?
• In Six Sigma, the Analyze phase uses data to identify cause-effect relationships.
• Which concept is demonstrated by the Levey-Jennings Chart?
• A group of specimens analyzed and reported together is called what?
• If a control mean is 100 and SD is 5, a result of 95 yields Z = (95-100)/5 = -1. Which statement is true?
• Westgard rules are generally applied when the number of control measurements per run is:
• What is external quality assessment (EQA) and how does it differ from proficiency testing?
• Which Westgard rule is triggered by a single control value exceeding the mean by more than 2 standard deviations?
• What is the effect of increasing the mean while keeping SD constant on the Z-score for a fixed observed result?
• What is the primary use of a Shewhart control chart in monitoring instrument performance?
• What term describes the range that controls should fall within to ensure accuracy (Mean ± 2SD)?
• Describe the cycle of proficiency testing and how laboratories use results to improve.
• Which statement about Z-score is true?
• What is the first step when you observe drift in a control value over several days?
• Which statistic is the square root of the variance?
• Differentiate internal quality control from external quality control in a clinical lab.
• Which document records traceability to standards?
• When a reagent lot changes, what is a recommended approach?
• What is the standard retention period for QC records?
• What is the primary purpose of ISO 15189 in clinical laboratories?
• What does CAPA stand for in QC practice, and why is it important?
• How are internal QC control materials selected and what acceptance criteria are typically used?
• In QC results, which binary classification is commonly used?
• An abrupt change from the established mean on a QC chart is called what?
• What is a primary responsibility of the quality manager in the laboratory QC program?
• Which plot is used to display control results on the Y-axis against time on the X-axis?
• Dynamic range defines which of the following?
• Which regulation mandates quality control in clinical laboratories in the United States?
• What is the standard deviation abbreviated as?
• What are typical elements of an internal audit review?
• In a Levey-Jennings plot, which statement is true about axes?
• In DMAIC, which phase investigates root causes and validates root causes against captured data?
• In DMAIC, which phase monitors the system after changes to ensure gains are sustained?
• Which item is NOT typically included in a quality control plan?
• Linearity and dynamic range define method applicability. Which statement is correct?
• Which Westgard rule is violated when ten consecutive control measurements fall on one side of the mean?