Transcript Presentation - Pakistan Society Of Chemical Pathology

PAKISTAN SOCIETY OF CHEMICAL PATHOLOGISTS
ZOOM SERIES OF LECTURES
ZT 24. QUALITY MANAGENT 1
BRIG AAMIR IJAZ
MCPS, FCPS, FRCP (EDIN), MCPS-HPE
HOD AND PROFESSOR CHEMICAL PATHOLOGY
AFIP RAWALPINDI
Specific Learning Outcome
At the end of this lecture the
students will be able to describe the
processes involved in Quality
Management.
Task 1
• Write FIVE Qs of total quality management
TQM Framework
MCQ NO 1
A laboratory manager is concentrating on the measures like
reducing
turnaround
time,
specimen
identification,
patient
identification and test utility. Which of the following term best
describes these processes:
A. Quality Assessment
B. Quality Control
C. Quality Improvement
D. Quality Laboratory Processes
E. Quality Planning
•
A. Quality Assessment
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Quality Assurance / Assessment (QA)
• An all inclusive / comprehensive system
monitoring the accuracy of test results where
all steps before, during and after the testing
process are considered.
• It includes pre-analytic, analytic and post
analytic factors
• Provides a structure for achieving lab and
hospital quality goals
7
Quality Control (QC)
• QC systems monitor the analytical process;
detect and minimize errors during the analysis
and prevent reporting of erroneous test
results.
• It is like ‘product testing’ in an industry
• It uses statistical analysis of test system data
• Requires Westgard Rules
8
Types of QC
• Daily
Internal
• Establishment of reference ranges
• Validation of a new reagent lot and/or
shipment
• Following instrument repair
9
Types of QC
External
Proficiency Testing
• Determination of laboratory testing performance by means
of intra-laboratory comparisons
• NEQAPP in Pakistan
• CAP, CLIA, The Joint Commission requirement
• Must be integrated within routine workload and analyzed
by personnel who are running the tests.
• Ongoing evaluation of results to correct for unacceptable
results
• Used to access employee competency
QC Material
Task 2
Please write the following control materials in the
order of the accuracy and reliability:
A. Lyophilized, bovine, un-assayed controls
B. Lyophilized, bovine, assayed controls
C. Liquid, human, and assayed controls
12
QC Materials
• Human or Bovine
• Lyophilized or Liquid
• Assayed or Unasssayed
13
Human or Bovine
• Why human is better than bovine?
• Values are closer to patient values (obviously)
• What precaution required in human?
• Infection free
14
Lyophilized or Liquid
• Which is better?
• Liquid
• Why?
• No pipetting error
• What is the disavantage
• Higher cost
15
Assayed or Unasssayed
• Why human is better than bovine?
• Values are closer to patient values (obviously)
• What precaution required in human?
• Infection free
Some Basic Statistics
MCQ No 2
Normal data means:
A. Labs own generated values
B. Result of disease free subjects
C. Result of healthy individuals
D. Symmetrical distribution
E. Values within reference range
D. Symmetrical distribution
18
Gaussian/Normal Distribution
• All values are
symmetrically
distributed around the
mean
• Characteristic “bellshaped” curve
• Assumed for all quality
control statistics
MCQ No 3
Which
of
the
following
is
measure of central tendency?
A.
Average
B.
Mean
C.
Median
D. Mode
E.
Standard deviation
D. Standard Deviation
NOT
a
20
Measures Of Central Tendency
• Mean (x̄) - the mathematical average of a group of numbers,
determined by adding a group of numbers (events) and dividing the
result by the number of events
• Median - determined as the ‘middle’ of a group of numbers that have
been arranged in sequential order. That is to say, there are an equal
number of numbers on either side of the ‘middle’ number. In an odd #
of observations, it is the middle observation. In an even # of
observations, average the two middle values.
• Mode - the number that appears most frequently in a group of
numbers. There can be more than mode, or none at all.
21
Standard Deviation (SD)
Is a mathematical expression of the dispersion
of a group of data around a mean.
SD 
  x  x
 n  1
2
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Standard Deviation :
SD 
  x  x
2
 n  1
n
=
the number of observations (how many numerical values )
Σ
=
the sum of … in this case, the sum of
x
=
X
= the value of each individual observation
x
 x
2
the mean value
The Standard Deviation is an expression of dispersion … the greater the
SD, the more spread out the observations are
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Standard Deviation and Probability
• For a set of data with a normal
distribution, a value will fall within a
range of:
• +/- 1 SD 68.2 % of the time
• +/- 2 SD 95.5% of the time
• +/- 3 SD 99.7% of the time
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Which is a Better Assay?
FSH Concentration
SD
1
0.09
5
0.25
10
0.40
25
1.20
100
3.80
Coefficient of Variation (CV) %
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Analyte:
FSH Concentration
SD
CV
1
0.09
9.0
5
0.25
5.0
10
0.40
4.0
25
1.20
4.8
100
3.80
3.8
•The smaller the CV, the more reproducible the results: more values are
closer to the mean.
•Useful in comparing 2 or more analytical methods
•Ideally should be less than 5 %
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Coefficient of Variation (CV)
• Indicates what percentage of the mean is represented
by the standard deviation
• Reliable means for comparing the precision or SD at
different units or concentration levels
• Expressed as a percentage
• CV% =
Standard deviation X 100
mean
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Establishment of a QC System
• Two or three levels of control material used
• A control is a material or preparation used to monitor
the stability of the test system within predetermined
limits
• Measure of precision and reproducibility
• Purpose: verify the analytic measurement range of
instrument for a specific analyte
28
Establishment of a QC System
Collecting data
• Run assay on control sample & manually enter control
results on chart
• One chart for each analyte and for each level of control
•
29
Collecting Data For QC
Charting techniques
• Levey Jennings chart is a graph that plots QC values in terms
of how many standard deviations each value is from the mean
•
30
Use of Standard Deviation
• Once you have determined the standard deviation, must
use the information to evaluate current/ future analysis.
• Most labs make use of ± 2 SD or 95% confidence limit.
To put this into a workable form, you must establish the
range of the ± 2 SDs
31
So, How Do We Determine The Range Of
Acceptable Results ?
Scenario
• Mean of group of control values = 104 mg/dL
• Standard Deviation = ± 5 mg/dL
• Determine the Range of ± 2SD; (which will allow you to evaluate
acceptability of performance of the control on subsequent days.)
• Is a control value of 100 mg/dL acceptable?
THANK YOU