(M) Lec 1: Quality Management in Clinical Chemistry Flashcards
(161 cards)
1
Q
Refers to over all program or system that ensures that the final results
generated by the laboratory has achieved and maintained a specified quality
A
Quality assurance
2
Q
3 phases of quality assurance
A
Pre-analytical, Analytical, Post-analytical
3
Q
These refer to which phase of QA:
Requisition of laboratory test
Patient preparation
Specimen collection
Specimen handling, processing, storage
A
Pre-ana
4
Q
These refer to which phase of QA:
Specimen analysis
Quality of reagent
Efficiency of instrument
Analytical skill proficiency of MedTech
A
Analytical
5
Q
These refer to which phase of QA:
Interpolation of results
Reporting of Results
Recording of Results
A
Post-ana
6
Q
Process of monitoring the characteristics of the analytical processes and detect analytical errors during testing
A
Quality control
7
Q
What does QC aims to ensure?
A
Precision and accuracy
8
Q
The objective of this is to:
Check quality of reagents
Monitor stability of machine
Monitor personnel errors/technical errors
A
QC
9
Q
T or F:
Quality control is defined as the overall program that ensures that final results reported by the laboratory are correct
A
False (QA)
10
Q
T or F:
Quality control refers to the measures that must be included during each test run to verify that the test is working properly
A
True
11
Q
This aims to ensure that the results generated by the tests are correct
A
Quality control
12
Q
What is the overall program that ensures that final results reported by the laboratory are correct?
A
QA
13
Q
What are the types of QC?
A
- Internal/ Intralaboratory Quality Control
- External/ Interlaboratory Quality Control
14
Q
Refers to:
Precision of laboratory tests
Applied to all work processes and to every test done in the laboratory
Based on the results of control specimens and patient `specimens
A
Internal/Intralaboratory QC
15
Q
These refer to:
Pattern recognition
Delta Check
Randomized duplicate specimens
Average of normals
A
Internal/Intralaboratory QC
16
Q
Refers to:
Accuracy of laboratory tests
Proficiency testing programs
A
External/Interlaboratory QC
17
Q
Ability to recognize pattern
A
Pattern recognition
18
Q
Compares past and present result
A
Delta check
19
Q
One patient sample is divided into two; requires that the result of the two specimen must be the same to ensure precision
A
Randomized duplicate specimens
20
Q
In external QC, where is the sample coming from?
A
Reference lab
21
Q
Ref lab for CC
A
Lung Center of the Philippines
22
Q
T or F:
Difference of >1 in external QC means not agreement with other lab
A
False (diff of >2)
23
Q
Ability of an analytical method to measure the smallest concentration of the analyte of interest
A
Analytical sensitivity
24
Q
Ability of an analytical method to measure only the analyte of interest
A
Analytical specificity
25
T or F:
Analytical sensitivity and analytical specificity are the same as diagnostic specificity and sensitivity
False
26
Nearness or closeness of the assayed value to the true or target value
Accuracy
27
Ability of an analytical method to give repeated results on the same sample
Precision
28
Reflects reproducibility
Precision
29
T or F:
In theory: It is impossible to have a method that is accurate but imprecise, but the overall average of repeat values is near the true value
False (possible)
30
T or F: In Practice: If a method is
imprecise, it is usually also
inaccurate
True
31
Degree by which a method is easily repeated
Practicabiltiy
32
Ability to maintain accuracy and precision over an extended period of time
Reliability
33
Ability to detect the proportion of individuals with a disease who test positively with the test
Diagnostic Sensitivity
34
Ability to detect the proportion of individuals without the disease who test negatively with the test
Diagnostic Specificity
35
Difference between the measured value and the mean expressed as a number of SD
SD Index
36
What are the three SD Index?
SDI of O- accurate/100% agreement
SDI of 3- inaccuracy
SDI of 2- investigate action
37
SDI that refers to accurate/100% agreement
SDI of O
38
SDI that refers to inaccuracy
SDI of 3
39
SDI that refers to investigate action
SDI of 2
40
These refer to:
Resembles human sample
Inexpensive and stable for long periods
No communicable disease
No matrix effects/known matrix effects
With known analyte concentrations
Convenient packaging for easy dispensing and storage
Preferrable lyophilized
Characteristics of a QC material
41
Lyophilized control solution must be stored in which temperature?
Room temp
42
T or F:
Control solution is a sample of known quantity of all analytes
False (several analytes only)
43
What is run alongside patient samples?
Control solution
44
2 levels control solution
Level I
Normal
45
2 levels control solution
Level II
Abnormal
46
3 levels control solution
Level I
Low normal
47
3 levels control solution
Level II
High normal
48
3 levels control solution
Level III
Very abnormal
49
T or F:
Control solution can be commercially and noncommercially prepared
True
50
Familiarize the sources of control slution
Fasting donor
Blood bank plasma
Left-over sera
Abbatoir blood
51
Refers to:
Contains a known amount of
analyte
A specific analyte is present
Used for calibrating an assay
method
Standard solution
52
Ussed to read out any absorbance caused by reagent or serum
Blank solution
53
Types of blank solution
Test or Serum blank
Reagent blank
Water blank
54
Variations/types of errors
Random Error
Systematic Error
Clerical Error
55
Also called as interdeterminate error
Random error
56
› Measures “imprecision”
› Errors that occurs without any real pattern
› Causes: due to instrument, operator, and environmental conditions
Random error
57
The following causes which type of error?
Pipetting errors
Mislabeling of samples
Temperature fluctuation
Improper mixing of sample and reagent
Dirty optics
Voltage fluctuations
Random error
58
Also called determinate error
Systematic error
59
› Measures “ Inaccuracy”
› Error that is continuous and affects all results equally
› Measure of agreement between the measured quantity and
true value
Systematic error
60
The following causes which type of error?
Calibration problems
Deterioration of reagents and control materials
Unstable and inadequate reagent blanks
Contaminated solutions
Failing instrumentation
Poorly written procedures
Systematic error
61
Two variations/types of systematic error
Constant error
Proportional error
62
Systematic error that is not dependent on the amount of analyte present
Constant error
63
Systematic error that is dependent on analyte concentration
Proportional error
64
Type of error that includes handwritten labels and request forms
Clerical error
65
T or :
Clerical errors occur in pre-analytical, analytical, and post-analytical phase
True
66
Refers to:
› Measure of central tendency
› Average of all the data points or values
Mean
67
Middle data point observed once data are arrange in descending or ascending order
Median
68
Value that occurs with the greatest frequency
Mode
69
Difference between the highest and lowest values in a set of data
Range
70
Measure of variability
Variance
71
Measure of the average squared distance of data points from the mean
Variance
72
Measure of precision
Standard dev
73
Measure of the dispersion of values from the mean
Standard dev
74
Percentile expression of the mean
Coefficient of Variation
75
Total Percent Error
Coefficient of Variation
76
Index of precision
Coefficient of Variation
77
Limits between which we expect a specified proportion of
population to lie
Confidence intervals or limits
78
Familiarize the usual confidence limits
68.2%= +/- 1SD
95.5 %= +/- 2SD
99.7%= +/- 3SD
79
T or F:
To be precise, the mean should be near the individual results
False (accurate)
80
T or F:
To be precise, the individual results should be near each other
True
81
What are the measures of precision?
SD, CV and variance
82
Relationship between SD and precision
Inversely proportional (the higher the SD, the less precise it is)
83
Relationship between variance and precision
Inversely proportional (the higher the variance, the less precise it is)
84
Relationship between COV and precision
Inversely proportional (the higher the COV, the less precise it is)
85
What are the quality control charts?
Gaussian Curve
Cumulative Sum Graph
Youden/Twin Plot
Shewhart Levey-Jennings Char
86
Refers to Normal Frequency Curve, Normal Distribution Curve
Gaussian Curve
87
The curve that results from the data that have a
normal distribution forming a bell-shape
Gaussian Curve
88
Other name for Gaussian Curve
Bell-shaped Curve
89
Population of subject of Gaussian Curve
At least 100
90
T or F: In the Gaussian Curve, data elements are centered around the mean with most elements close to the mean
True
91
Refers to a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean, and is also known as the Gaussian distribution
Normal Distribution
92
This gives the earliest indication of systematic error
Cumulative Sum Graph
93
This calculates the difference between Qc results and the target means and is done by subtracting the mean from the individual values and the cumulative differences are plotted
CUMSUM
94
Refers to:
Twin Chart
Used to compare results
Used to compare method using different samples or one sample using two different methods
Youden/Twin Plot
95
Refers to:
Most widely used system in clinical laboratories
Allows laboratorian to apply multiple rules without the aid
of computer
Shewart Levey-Jennings Chart
96
A graphic representation of the acceptable limits of variation in the results of an analytical method
Shewhart Levey-Jennings Chart
97
What error is being detected in Shewart Levey-Jennings Chart?
Both random and systematic error
98
System that allows good visual representation of precision and
relative accuracy, easy to interpret
Shewhart Levey-Jennings Chart
99
Error detected by Youden Chart?
Systematic error
100
Error detected by CUMSUM
Systematic error
101
A Shewhart Control Chart depend on the use of how many QC specimen?
1
102
Familiarize how Shewhart Control Chart is being developed
Put up the 1QC specimen for atleast 20 or more assay runs and record down readings
Calculate the mean and standard deviations (SD)
Make a plot with the running day on the x axis and readings on the y axis
Draw the lines across the y axis for the following:
Mean, +/- 1SD, +/- 2SD, +/- 3SD
Plot the reading obtained for the 1 QC specimen for `subsequent assay run
103
What are the errors that ca be observed on LJ Chart?
Trend, Shift, Oulier
104
Error on LJ Chart that refers to:
Gradual change in the mean that proceed in one direction
Control values either increases or decreases for six consecutive days
Causes: Deterioration of reagents, light source, control materials
Trend
105
How many days can control values increase or decrease for it to be considered a trend?
Six consecutive days
106
Causes of trend as an error on LJ Chart?
Deterioration of reagents, light source, control
materials
107
Error on LJ Chart that refers to:
An abrupt change in the mean that becomes continuous
Control values that distribute themselves on one side or either side of the mean for six consecutive days
Causes: improper calibration of instrument, new lots of standards and reagents
Shift
108
How many days can control values distribute themselves on the sides of the mean for it to be considered as a shift error on LJ Chart?
Six consecutive days
109
Causes of shift as an error on LJ Chart?
improper calibration of instrument, new lots of
standards and reagents
110
Error on LJ Chart that refers to:
Control values that are far from the main set of values
Highly deviating values
Random or Systematic errors
Outlier
111
Set of control and patient specimens assayed, evaluated and reported together
Analytical Run
112
Current results compared to the previous/past result
Delta Check
113
Measured concentration is equal to the actual concentration
Linear Range/Dynamic Range
114
Analytical testing performed outside the confines of the central lab usually by non-laboratorian personnel
Point of care Testing
115
Used to measure systematic errors or inaccuracy caused by substances other than the analyt
Interference Experiments
116
Example of substances that can cause inaccuracy in Interference Experiments
Hemoglobin, Lipids, bilirubin, anti-coagulants
117
This experiment shows wether a method measures all the analytes or only part of it
Recovery Experiment
118
This refers to the usual values for a healthy population that represents 95% central tendency
Reference Limit, Reference Interval, Reference Value
119
Its purpose is to determine how much of analyte can be detected in presence of all other compounds in the matrix
Recovery studies
120
T or F: Recovery studies determine if the method is able to accurately measure an analyte
True
121
T or F: In Reference Value, specific measurement are performed on a large number of healthy individuals (age and sex)
True
122
How many patients do you need each age and sex category to establish a Reference Value/Reference Interval?
100/120
123
Familiarize the factors that affect establishing Reference Values
Analytical method used
Specimen collection procedure
Composition of reference population
Criteria of exclusion and inclusion
Physiologic and environmental factpr
124
Refers to:
A new method is evaluated by comparing it with a reference method
Comparison of Methods
125
T or F:
Westgard recommends that at least 30 samples and preferrably 120 samples should be run by both method
False (40 - 100)
126
What are the measures of accuracy?
Recovery experiment
Interference studies
Patient sample
comparison
127
Enumerate the measures of precision.
CV
SD
Variance
128
Multiple quality control
Westgard’s Multirule System
129
In Westgard’s Multirule System, this is to indicate if the analytical process is “in
control” or “out of control”
Control rule
130
What are the control rules in Westgard’s Multirule System?
1-2s
1-3s
2-2s
4-1s
R-4s
10x
subscript yang after ng hyphen idk asan subscript dito
131
Westgard Control Rules
One control result exceeds the mean by
more than +/- 2SD
Warning or rejection rule
Detects random error
1-2s
132
Westgard Control Rules
One control result exceeds the mean by
more than +/- 3SD
Detects random error
1-3s
133
Westgard Control Rules
Two consecutive control results exceed the
mean by 2 more than 2SD
Response most often to systematic errors
Must lie in the same direction from the mea
2-2s
134
Westgard Control Rules
Four consecutive control results exceeds the
mean by more than 1SD
Must lie in the same direction from the mean
Responsive to systematic error
4-1s
135
Westgard Control Rules
Difference between two consecutive controls is greater than 4SD
Assay values in opposite direction from each other
Responsive to random errors or increased imprecision
R-4s
136
Westgard Control Rules
Ten consecutive results are on the same side of `the target mean
Systematic error
10-x
137
T or F:
If QC is out of control, you can still fix it by testing and testing again
False (stop testing)
138
T or F:
Each part of the gaussian curve is the percentage per SD
True
139
In Gaussian curve/bell curve, what could it mean if it lies between 2-3 SD?
Potential error
140
In Gaussian curve/bell curve, what could it mean if it lies more than 3 SD from the mean?
Needs corrective action
141
T or F: If the curve becomes wider or skewed, it's still in normal distribution
False (there is an error)
142
Disadvantage of Shewart Levey Jennings Chart
Time consuming
143
Other name for Shewart Levey
Dot/shoe chart
144
How many directions does the trend proceed to?
One
145
Trend and shift are example of (random/systematic) errors
Systematic
146
T or F: A change in the control value for 10 days can be considered either a trend or shift depending whether it's abrupt or gradual and its direction
False (does not follow 10 x rule)
147
T or F: A change in the control value for 5 days can be considered either a trend or shift depending whether it's abrupt or gradual and its direction
False (does not follow the 6 day rule)
148
In what manner should Confidence limits should be reported?
By range
149
Which systematic error does CUSUM specifically detect?
Trend
150
Most common method of CUSUM
VMAS
151
Which systematic error does Twin Plot specifically detect?
None (not specific)
152
Most important statistical parameters under LJ Chart
Mean, SD, and CL
153
In LJ Chart, running day is plotted on (X/Y axis)
X axis
154
In LJ Chart, reading is plotted on (X/Y axis)
Y axis
155
In LJ Chart, what are calculated?
Mean and SD
156
In LJ Chart, what are drawn across the y axis?
Mean, +/- 1SD, +/- 2SD, +/- 3SD
157
LJ Chart is mostly done with what curve on the side?
Gaussian curve (to check if may bell shape pa rin)
158
T or F: You cannot use different kinds of lines to differentiate mean from 1SD, 2SD, etc
False (up to you)
159
T or F: Shift passes the mean in LJ chart
False (papuntang gilid lang)
160
T or F: Trend goes on sides of the mean in LJ chart
False (Shift 'yun)
161
A value must pass how many SD from the mean for it to be considered as outlier usually?
+/- 3SD
