Quality Control Flashcards
Quality
characteristics of a product which meets expected criteria of consumer (customer)
Control
solution that resembles human sample that is used for QC purposes only
Standard
colorless solution with known concentration of substances used for calibration
Specificity
ability of a method to measure the analyte of interest ONLY
Sensitivity
ability of a method to measure analytes even at its lowest concentration
Accuracy
nearness of measured value to that of the target value
Precision
nearness of measured values to each other
Diagnostic specificity
ability of a method to detect a population of individuals absent of disease process
Intralab QC (Internal QC)
- control samples are run simultaneously with a patient to ensure reliability of methods and result.
- used for daily monitoring of accuracy and precision of method used
- detects random and systematic errors.
Diagnostic sensitivity
ability of a method to detect a population of individuals having presence of disease
Interlab QC (External QC)
- Laboratories are given sample with unknown concentrations for them to test
- Results are compared with other laboratories thus maintaining long term accuracy to methods utilized
- Results difference of >2SD = disagreement with other lab included
Mean
- average of a set of values (mean=Σx/n)
- measures central tendency
Median
midpoint of a set of values
Mode
most frequent among all values/data
Range
Simplest expression of spread or distribution
Standard Deviation
measure of dispersion of values to that of the mean
Coefficient of variation
- Mean expression in percentile
- Index of precision
Variance
- square of SD
- V = SD^2
T-test
- Used to assess if there is a statistical difference between means of 2 groups of data
