Question 1

Using only the 13s rule to evaluate a control run has a low risk of falsely rejecting a run.What is a common concern about using only this rule?

Accepted Answer

A)   The frequency of acceptable rejection is 25%.
B)   The number of random errors is high.
C)   The rate of error detection is low.
D)   The rule cannot detect a systemic error. C

Question 2

What is a concern about the single rule that dictates that control values must fall within two standard deviations of the mean?

Accepted Answer

A)   It can only be trusted when greater than ten different controls have been tested.
B)   It can trigger false alarms that cause rejection of acceptable runs.
C)   It is insufficient to detect errors created by compromised controls.
D)   It is only applicable to instruments previously calibrated by the International Standards Committee. B

Question 3

An automated cell counter consistently produces red blood cell readings that are 20% too low.What type of error is this considered?

Accepted Answer

A)   Absolute
B)   Random
C)   Systematic
D)   Variable

Question 4

Which of the following is true regarding constant systematic errors?

Accepted Answer

A)   The slope and the x-intercept of the regression line are affected.
B)   The slope of the regression line differs from the true value.
C)   The x-intercept of the regression line becomes equal to the y-intercept.
D)   The y-intercept of the regression line differs from the true value.

Question 5

How can the effects of random error be minimized?

Accepted Answer

A)   By averaging a large number of results
B)   By having all tests performed by the same technician
C)   By multiplying the results by a constant standard
D)   By performing control tests in a fixed environment

Question 6

A Levey-Jennings chart is created to analyze a set of data.The last consecutive eight data points gradually move downward away from the mean.What type of aberration would this be considered?

Accepted Answer

A)   Outlier
B)   Shift
C)   Trend
D)   Variance

Question 7

The following plot is a Levey-Jennings chart. 
Which of the following is true about the data point noted by the arrow?

Accepted Answer

A)   It indicates a shift has occurred.
B)   It is an outlier.
C)   It suggests the data are trending downward.
D)   None of the above

Question 8

The following is a Levey-Jennings chart. 
Which of the following is the best conclusion based on the circled data?

Accepted Answer

A)   The data fall within 2 SD of the mean; so the recent run can be accepted.
B)   The data have several outliers; so the recent run must be rejected.
C)   The data comply with at least 3 of the Westgard Rules; so the recent run may be accepted.
D)   The data violate the Westgard Rule of 10ₓ; so the recent run must be rejected. D

Question 9

What are the rules,as stated by CLIA,for the number and frequency of control tests that a laboratory should run on a qualitative assay?

Accepted Answer

A)   A test of one positive and one negative control must be run at least once per day.
B)   A test of three controls at unknown concentrations must be run at least twice per day.
C)   A test of two controls at different concentrations must be run at least once per day.
D)   A test of two different positive controls must be run at least twice per day.

Question 10

One of three quality-control results for an instrument violates the 12s rule.What is the proper course of action?

Accepted Answer

A)   Continue to run samples but mark the results as "pending QC approval."
B)   Use a back-up instrument for running patient specimens until resolution of the problem.
C)   Refrain from running patient specimens until resolution of the problem.
D)   Because the 12s rule is only a warning, continue running patient specimens.

Question 11

Which of the following is a crucial feature of a substance used as a control?

Accepted Answer

A)   It should be constructed from real human tissues or fluids.
B)   It should be provided and maintained by the manufacturer of the assay or equipment.
C)   It should be stored at 32°C to prevent degradation.
D)   It should mimic the chemical and physical properties of a typical patient specimen.

Question 12

On a Levey-Jennings chart,the final single data point falls outside the +3 SD mark.According to Westgard Rule 13s,should the most recent run be accepted?

Accepted Answer

A)   No, because any data point that does not exactly equal the mean value must be rejected.
B)   No, because the data point falls outside the accepted range of  xˉxˉ±3s \bar{x} \bar{x} \pm 3 s xˉxˉ±3s 
C)   Yes, because runs are rejected only if six or more consecutive data points deviate by greater than +3 SD from the mean.
D)   Yes, because values that fall beyond positive standard deviations from the mean are still within the acceptable range.

Question 13

Which of the following is true regarding proportional systematic errors?

Accepted Answer

A)   The slope and the x-intercept of the regression line are affected.
B)   The slope of the regression line differs from the true value.
C)   The x-intercept of the regression line becomes equal to the y-intercept.
D)   The y-intercept of the regression line differs from the true value.

Question 14

The following is a Levey-Jennings chart measuring a single control. 2s B)  Rule 13s C)  Rule 22s D)  Rule R4s" class="answers-bank-image d-inline" rel="preload" >
What Westgard Rule is violated in this chart?

Accepted Answer

A)   Rule 12s
B)   Rule 13s
C)   Rule 22s
D)   Rule R4s

Question 15

Which of the following is true about Rule 12s?

Accepted Answer

A)   A control violates the rule only when it falls more than 3 SD from the mean.
B)   A control that deviates up to -4 SD from the mean is not considered in violation.
C)   A control will violate the rule approximately once in every 20 acceptable runs.
D)   A violation of this rule should result in rejection of the recent runs.

Question 16

Many laboratories have the policy that,in the event of a Rule 12s violation,the control must be repeated.If the result is in range,then patient specimens may be run.Why is this common practice controversial?

Accepted Answer

A)   It circumvents the absolute rejection rule where any rule violation automatically results in rejection.
B)   It does not follow the standard procedure of verifying a rejection under a single rule using multirule tests.
C)   It supplants an internal quality-control procedure that was designed specifically to minimize the rate of false rejection.
D)   All of the above.

Question 17

Which of the following explains the primary use of Levey-Jennings charts?

Accepted Answer

A)   Determination of the best fit line through a large set of data points
B)   Generation of a standard curve from which information about a sample, such as concentration, can be determined
C)   Identification of outliers, trends, and shifts in data that may indicate a malfunction or other problem
D)   Maintenance of laboratory equipment in compliance with the International Sensitivity Index (ISI)

Question 18

Which of the following explains how a violation of Westgard Rule R₄s is identified?

Accepted Answer

A)   The difference between two consecutive data points is at least 4 SD, and one data point liesabove  xˉ+2s \bar{x}+2 s xˉ+2s  and the other lies below  xˉ−2s \bar{x}-2 s xˉ−2s . 
B)   The result from 2 single control run lies outside the range  xˉ±3s \bar{x} \pm 3 s xˉ±3s 
C)   The result from one control lies above  xˉ+2s \bar{x}+2 s xˉ+2s , and the result from a different control liesbelow  xˉ−3s \bar{x}-3 s xˉ−3s .
D)   Both A and C are correct.

Exam 11: Quality Control

Using only the 1_3s rule to evaluate a control run has a low risk of falsely rejecting a run.What is a common concern about using only this rule?

Correct Answer
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C

What is a concern about the single rule that dictates that control values must fall within two standard deviations of the mean?

Correct Answer
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B

An automated cell counter consistently produces red blood cell readings that are 20% too low.What type of error is this considered?

Correct Answer
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Which of the following is true regarding constant systematic errors?

Correct Answer
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How can the effects of random error be minimized?

Correct Answer
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A Levey-Jennings chart is created to analyze a set of data.The last consecutive eight data points gradually move downward away from the mean.What type of aberration would this be considered?

Correct Answer
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The following plot is a Levey-Jennings chart. Which of the following is true about the data point noted by the arrow?

Correct Answer
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The following is a Levey-Jennings chart. Which of the following is the best conclusion based on the circled data?

Correct Answer
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D

What are the rules,as stated by CLIA,for the number and frequency of control tests that a laboratory should run on a qualitative assay?

Correct Answer
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One of three quality-control results for an instrument violates the 1₂s rule.What is the proper course of action?

Correct Answer
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Which of the following is a crucial feature of a substance used as a control?

Correct Answer
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On a Levey-Jennings chart,the final single data point falls outside the +3 SD mark.According to Westgard Rule 1₃s,should the most recent run be accepted?

Correct Answer
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Which of the following is true regarding proportional systematic errors?

Correct Answer
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The following is a Levey-Jennings chart measuring a single control. What Westgard Rule is violated in this chart?

Correct Answer
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Which of the following is true about Rule 1₂s?

Correct Answer
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Many laboratories have the policy that,in the event of a Rule 1₂s violation,the control must be repeated.If the result is in range,then patient specimens may be run.Why is this common practice controversial?

Correct Answer
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Which of the following explains the primary use of Levey-Jennings charts?

Correct Answer
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Which of the following explains how a violation of Westgard Rule R₄s is identified?

Correct Answer
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Exam 11: Quality Control

Using only the 13s rule to evaluate a control run has a low risk of falsely rejecting a run.What is a common concern about using only this rule?

Correct AnswerverifiedC

What is a concern about the single rule that dictates that control values must fall within two standard deviations of the mean?

Correct AnswerverifiedB

An automated cell counter consistently produces red blood cell readings that are 20% too low.What type of error is this considered?

Correct AnswerverifiedShow Answer

Which of the following is true regarding constant systematic errors?

Correct AnswerverifiedShow Answer

How can the effects of random error be minimized?

Correct AnswerverifiedShow Answer

A Levey-Jennings chart is created to analyze a set of data.The last consecutive eight data points gradually move downward away from the mean.What type of aberration would this be considered?

Correct AnswerverifiedShow Answer

The following plot is a Levey-Jennings chart. Which of the following is true about the data point noted by the arrow?

Correct AnswerverifiedShow Answer

The following is a Levey-Jennings chart. Which of the following is the best conclusion based on the circled data?

Correct AnswerverifiedD

What are the rules,as stated by CLIA,for the number and frequency of control tests that a laboratory should run on a qualitative assay?

Correct AnswerverifiedShow Answer

One of three quality-control results for an instrument violates the 12s rule.What is the proper course of action?

Correct AnswerverifiedShow Answer

Which of the following is a crucial feature of a substance used as a control?

Correct AnswerverifiedShow Answer

On a Levey-Jennings chart,the final single data point falls outside the +3 SD mark.According to Westgard Rule 13s,should the most recent run be accepted?

Correct AnswerverifiedShow Answer

Which of the following is true regarding proportional systematic errors?

Correct AnswerverifiedShow Answer

The following is a Levey-Jennings chart measuring a single control. What Westgard Rule is violated in this chart?

Correct AnswerverifiedShow Answer

Which of the following is true about Rule 12s?

Correct AnswerverifiedShow Answer

Many laboratories have the policy that,in the event of a Rule 12s violation,the control must be repeated.If the result is in range,then patient specimens may be run.Why is this common practice controversial?

Correct AnswerverifiedShow Answer

Which of the following explains the primary use of Levey-Jennings charts?

Correct AnswerverifiedShow Answer

Which of the following explains how a violation of Westgard Rule R₄s is identified?

Correct AnswerverifiedShow Answer

Using only the 1_3s rule to evaluate a control run has a low risk of falsely rejecting a run.What is a common concern about using only this rule?

Correct Answer
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C

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B

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D

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One of three quality-control results for an instrument violates the 1₂s rule.What is the proper course of action?

Correct Answer
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Correct Answer
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On a Levey-Jennings chart,the final single data point falls outside the +3 SD mark.According to Westgard Rule 1₃s,should the most recent run be accepted?

Correct Answer
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Correct Answer
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Correct Answer
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Which of the following is true about Rule 1₂s?

Correct Answer
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Many laboratories have the policy that,in the event of a Rule 1₂s violation,the control must be repeated.If the result is in range,then patient specimens may be run.Why is this common practice controversial?

Correct Answer
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Correct Answer
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Correct Answer
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