Quality Control Flashcards
The closeness between a test reuly and the true value
Accuracy
Quality control chart
Levey jennings chart
The closeness of test results to one another
Precision
A measure of precision or how well the measurement system reproduces the same result over time
Quality control
A chart that contains bith bar and line graph
Pareto chart
Comparison of the standard deviation of two samples
Coefficient of variation CV
The ability to produce more true positive than few false negative
Diagnostic sensitivity
For long term accuracy and precision
Interlab
For short term quality and precision
Intralab
Mislabelling of samples, temperature changes, dirty optics, voltage fluctualtions
Random error
Analyses of control sample together with the patient specimens
Intralab
Also known as slope or percent error
Proportional error
Present in all measurement and causes imperfection
Random error
It is independent of sample concentration
Constant error
A measure of central tendency
Mean
Error due to instruments operator and environmental conditions
Random error
A neasure of accuracy
Mean
A measure of difference of values from the mean
Standard deviation
An index of precision
Coefficient of variation
The ability to produce more true negatives than few false positive
Diagnostic specificity
Used to determine rederence values
Gaussian curve
Uses computer implementation
Cumulative sum graph
Difference between the tested value and the target value
Constant error
Difference between qc results and the target means
Cusum graph
Also known as twin plot
Youden plot
A gradual loss of reliability
Trend
Control values that can either increase or decrease dor 6 consecutive days
Trend
A graphic representation of the acceptable limits of variation
Shewhart levy jennings chart
Control values that distribute themselves on one side or either side
Shift
A value taht are far from the main set of values
Outliers
Dergree of flatness or sharpness of peak of a set of values having a gaussian distribution
Kurtosis
Confidence limit applicable
95% (+/-2sd)
Control and patient specimen assayed evaluated and reported together
Analytical run
Examples of systematic error
Trend Outliers Shift 2 2s 4 1s 10x
Most commonly used patient based qc technique
Delta check
Error that cant be easily detected or observed
Random error
Error that causes inaccuracy
Systematic error
Produces constant difference
Sustematic error
Old or contaminated reagents, poor written proceedures, incorect sample and reagent colume
Systematic error
Involves proficiency testing program
Interlab
Example of random error
Outliers
R 4s
1 2s
1 3s
