MLAB 2360 Clinical I
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Laboratory Quality Control
Points: 55
Name:______________________
Date: ________________________
Part 1: 1 pt each
1. The main programs of the quality assurance department are:
a. Risk management, in-service and continuing education, safety programs,
quality control and peer review.
b. Human resources, national laboratory week committee, and quality control
documentation.
c. Diversity, red ribbon week, and health and safety education.
d. Laboratory operations, research and development.
2. Statistical methods commonly used to evaluate quality control data in the clinical
lab is/are:
a. T-test, z-test, and F-test.
b. Numerical statistics and graphic techniques.
c. Regression analysis and Pearson’s correlation coefficient
d. X2 (chi-square) tests.
3. Precision of a method is best defined as:
a. Agreement between replicate measurements obtained from the sample
analyzed by the test method under prescribed conditions.
b. Allowable bias.
c. Accuracy.
d. Closeness of the agreement between the result of the measurement and a
true value of the measured
4. Systematic error causes:
a. Shifts and trends on control (Levey Jennings) charts.
b. Outliers on control charts.
c. Random error.
d. Imprecision.
5. Select one example of the postanalytic phase:
a. Specimen preparation
b. Specimen analysis
c. Clinician receives the test result
d. Specimen collection
MLAB 2360 Clinical I
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Part 2: 2pts each
For each of the following Levey-Jennings charts, circle the choice
“acceptable” or “out of control”. For each that is “out of control”, tell
Westgard rule is violated and the first day that QC must be rejected.
NOTE: There may be more than one “out of control” problem for each chart.
Use the rules Westgard rules given in the QC powerpoint (Shift, Trend, 13s,
22s, R4s, 41s).
Example:
Levey-Jennings Control Chart
100
+3SD
+2SD
+1SD
Mean
95
90
-1SD
-2SD
-3SD
85
80
1
3
5
7
9
11
13
Days or Runs
On all of the Levey Jennings charts in this exercise: Mean is 90 and the Control range is 85-95**
**Control Range= ±2SD which represents the 95% confidence interval**
Acceptable
Out of Control
If unacceptable (out of control), Explanation: This chart shows a trend
(6 consecutive points dropping or rising) from days 3 through 8, so the
results are out of control on day 8.
MLAB 2360 Clinical I
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QC Levey-Jennings Chart 1:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
11
13
Days or Runs
1. Acceptable
Out of Control
If unacceptable, Explanation:
QC Levey-Jennings Chart 2:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
Days or Runs
2. Acceptable
Out of Control
If unacceptable, Explanation:
11
13
MLAB 2360 Clinical I
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QC Levey-Jennings Chart 3:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
11
13
Days or Runs
3. Acceptable
Out of Control
If unacceptable, Explanation:
QC Levey-Jennings Chart 4:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
Days or Runs
4. Acceptable
Out of Control
11
13
MLAB 2360 Clinical I
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If unacceptable, Explanation:
QC Levey-Jennings Chart 5:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
11
13
Days or Runs
5. Acceptable
Out of Control
If unacceptable, Explanation:
QC Levey-Jennings Chart 6:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
Days or Runs
6. Acceptable
Out of Control
11
13
MLAB 2360 Clinical I
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If unacceptable, Explanation:
QC Levey-Jennings Chart 7:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
11
13
Days or Runs
7. Acceptable
Out of Control
If unacceptable, Explanation:
QC Levey-Jennings Chart 8:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
Days or Runs
8. Acceptable
Out of Control
If unacceptable, Explanation:
11
13
MLAB 2360 Clinical I
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QC Levey-Jennings Chart 9:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
11
13
Days or Runs
9. Acceptable
Out of Control
If unacceptable, Explanation:
QC Levey-Jennings Chart 10:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
Days or Runs
10. Acceptable
Out of Control
11
13
MLAB 2360 Clinical I
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If unacceptable, Explanation:
QC Levey-Jennings Chart 11:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
11
13
Days or Runs
11. Acceptable
Out of Control
If unacceptable, Explanation:
QC Levey-Jennings Chart 12:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
Days or Runs
12. Acceptable
Out of Control
11
13
MLAB 2360 Clinical I
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If unacceptable, Explanation:
QC Levey-Jennings Chart 13:
Levey-Jennings Control Chart
100
95
Mean = 90
Control
90
Range =
85-95
85
80
1
3
5
7
9
11
13
Days or Runs
13. Acceptable
Out of Control
If unacceptable, Explanation:
Part 3: 2pts each
1. Calculate the mean of the following set of numbers, SHOW YOUR WORK:
25,22,26,24,21,29,26,20,28,23
Mean:____________
2. Calculate the variance from the above values, SHOW YOUR WORK.
X
25
22
26
24
21
29
26
20
28
23
(X - Mean)2
X - Mean
TOTAL
MLAB 2360 Clinical I
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Variance:____________
3.
Calculate the standard deviation from the above values, SHOW YOUR WORK.
4. Calculate the mean of the following values, SHOW YOUR WORK:
82,85,90,86,91,90,81,86,94,89.
Mean: ___________
5. Calculate the variance from the above values (question 4), SHOW YOUR WORK.
X
82
85
90
86
91
90
81
86
94
89
(X - Mean)2
X - Mean
TOTAL
Variance:______________
6.
Calculate the standard deviation from the above values, SHOW YOUR WORK.
MLAB 2360 Clinical I
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Part 4: 3 pts each
1. Your lab manager asks you to create the new control range for the new lot of
hematology control level 1. The following 20 hemoglobin values are gathered to
determine the control limits. Using a calculator or website SD function, calculate and
record the mean, the standard deviation, and the 95% confidence interval for this set
of values.
4.2
4.7
4.3
4.4
4.0
4.9
4.7
4.6
4.7
4.9
5.0
4.1
4.2
4.7
Mean:__________ 1 SD:__________
4.6
4.0
4.4
4.5
4.8
4.4
95% Confidence range:________________
2. Given the results above, label the following Levey-Jennings Control chart with all of
the following:
Mean
Values for -3SD, -2SD, -1SD, +1SD, +2SD, +3SD
Result in mg/dL
Control 1 Hemoglobin
Levey-Jennings chart
AUGUST
1 2 3 4 5 6 7 8 9 10……
Day
.
MLAB 2360 Clinical I
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3. You have your Levey-Jennings Control chart ready. Your supervisor tells you to
begin using the lot. Record the first 10 days of Control 1 Hemoglobin results. In
your lab, you run controls once per day because you are a clinic open from 8-5pm.
Plot each data point on your labeled chart and circle whether the controls are
acceptable or “out.”
DAY of August
1= 4.5 mg/dl
2=4.2 mg/dl
3=4.1 mg/dl
4=4.6 mg/dl
5=4.7 mg/dl
ACCEPTABLE
6=4.8 mg/dl
7=4.4 mg/dl
8=4.4 mg/dl
9=4.2 mg/dl
10=4.9 mg/dl
OUT OF CONTROL
4. You run a normal serum glucose control and obtain a value of 78.4 mg/dL. The mean
for this control is 74.8 mg/dL and 1 SD has been calculated as 1.2. Is the value of
78.4 within 2SD (95% confidence interval)? Circle the correct answer.
YES
NO