Exam 5 Quality Management

Quality Management
The process of ensuring accurate lab results
Descriptive Statistics
Summarize important features of a group of data
Mean
Sum of the data points divided by the number of data points
Median
Middle data point in a set
Mode
The most frequent data point in a set
Range
Largest # – Smallest #
Standard Deviation
Dispersion; how data is spread around the mean
What is SD used to set?
Limits of acceptability (confidence limits)
Coefficient of Variation
Way of expressing SD in %
What is CoV good for comparing?
Tests reported in different units and concentrations
%CV = ?
(SD/X) x 100
Gaussian Distribution
Visual representation of the distribution of values around an established mean
What % of data falls between +/= 1 SD?
68%
What % of data falls between +/= 2 SD?
95%
What % of data falls between +/= 3 SD?
99%
Reference Interval Study
CAP requires that every lab either establish or verify reference intervals for any new test
How many volunteers are needed for Establishing a Reference Interval?
120+
How many volunteers are needed for Verifying a Reference Interval?
20+
When Verifying a Reference Interval, No more than what percent of the tested subjects must fall outside the vendor’s limits?
10%
When Establishing a Reference Interval, how do you determine the reference interval?
Mean +/= 2 SD
Diagnostic Efficiency
How good is a test at detecting or predicting the presence of a disease?
Diagnostic Sensitivity
proportion of persons with a disease who test positive
Diagnostic Specificity
proportion of persons without the condition who test negative
Precision Study
Detects any problems with test reproducibility
Describe Precious Study
2 controls
Run Twice a day
10 Days
Accuracy Study
Often use patient samples spiked with known analyte
Comparison-of-Methods Studies
Comparing patient results of new method with patient results of out-going method
What are some reasons for changing methods?
Cost, efficiency, TAT, personnel, safety, disposal, etc.
When performing Comparison-of-Methods Studies what is the recommended # of specimens to run by each method?
40-100
When performing Comparison-of-Methods Studies, specimens should be run by each method within how many hours of each other?
4 hours
When performing Comparison-of-Methods Studies,it is recommended that you spread the testing out over how many days?
8-20
With Linear Regression Analysis, Values by the current method are plotted on which axis?
X axis
With Linear Regression Analysis, Values by the new method are plotted on which axis?
Y axis
True or False:
Linear Regression Analysis – The agreement between the two methods
is estimated from the best straight line between the points
True
What does the Linear Regression Analysis provide?
Measures of Dispersion
Quality Control
The lab’s system for recognizing errors and to prevent reporting of incorrect patient values
Controls
Purchased materials that are tested and compared to the manufacturer’s predetermined target ranges
You should have a sufficient quantity of controls to last a minimum of how long?
1 year
For New Lots, Controls must be analyzed for at least how many days?
20 days
Confidence Limits
A control should fall within the 95% (2SD) Range
QC Charts: Levey-Jennings
Graphically show the values of a control over time
What are the 3 Types of Analytic Errors
Systematic/Systemic Error
Random Error
Dispersion
Dispersion
Wide scattering of control values
Dispersion may be caused by what 2 things?
System failure
Operator error
Random error
Unexpected error that affects precision
Can Random error be predicted?
No
What are 2 causes of Random Error?
Environmental
Operator error
Shift
Abrupt change in the analytical process
Trend
Gradual change in the analytical process
What is the following considered:
6 or more data points all falling above or all falling below the mean
Shift
What is the following considered:
Data points take either an upward or a downward direction
Trend
Systematic/Systemic Error
A factor that causes a constant error, either + or =
What are some causes of Systematic/Systemic Error
Poorly made standards or reagents
Failing instrumentation
Deteriorating reagents
Improper blanking
Poorly written procedure
Which type of Analytic Error Affects all samples in the run?
Systematic/Systemic Error
Westgard Rules
What to do when a control is out of range.
What is Westgard Rules based on?
@ Least 2 controls per run
1 2S
Warning
1 3S
1 control value falls outside +/= 3SD (random error)
Which 2 Westgard Rules are Random Error
1 3S & R 4S
2 2S
2 consecutive values fall outside +/= 2 SD on the same side of X
R 4S
1 control is >+2SD, the other is >-2SD
4 1S
4 Consecutive values that fall outside +/= 1 SD on the same side of X
10X
10 Consecutive values that fall on one side of the mean
Which 3 Westgard Rules are Systemic Errors?
10X, 4 1S, & 2 2S
Delta Check
A patient’s most recent test result is compared with a previous test result
What does Delta Check Detect?
Mislabeling, test errors, contamination, or a change in patient
What is it called when there is External Quality Control?
Proficiency Testing
Proficiency Testing
Designed to detect testing errors in a lab. Your lab results are graded and compared to all other participants in the program
True or False:
Proficiency Testing is required to maintain accreditation with TJC, CLIA, & CAP
True
What do Discrepant results require?
Investigation
If discrepancies aren’t fixed, what can happen?
The lab may lose the authority to perform patient testing to the analyte in question
Quality Improvement
A program designed to develop new, improved levels of performance
Lean
An idea designed to eliminate non-value adding steps;
Six Sigma
An idea designed to reduce variation
Which Quality Improvement is used to Reduce Cycle Time?
Lean
Which Quality Improvement is used to Reduce Error?
Six Sigma