les 7 Flashcards
Standard deviation squared. Assuming all sources
of error are independent of each other, total error is the sum of variances of individual sources of error
Variance
A statistic that describes the amount of
variance of a set of measurements about the mean value. It is
used to describe the random error of an analytical method
- Standard deviation
The interval between the beginning of one
event to the end of another event in the total testing process. Typically measured as the collection to reporting time or as the receipt of specimen in laboratory to reporting
time.
- Turnaround time
Part of specimen that is measured.
Material of known or assigned concentration used for assay calibration.
Standard
The lowest detection limit of an assay;
sometimes measured as the concentration of an analyte that can
be differentiated from a blank within a 95% confidence interval
Sensitivity, analytical
The ability of an analytical method to
determine solely the component(s) it purports to measure.
- Specificity, analytical
Test results that are within expected
parameters for about 95% of all individuals in a defined
healthy population. Values outside of the range are classified
as abnormal and may be associated with a pathological
condition
Amount (usually expressed as percentage) of
known quantity of an analyte that is measured when added
to a specimen
Recovery
A variance from expected that is not
reproducible or predictable
- Random error
A process for monitoring assay performance
to detect deviations from expected outcomes
Quality control
A systematic approach to continuously
analyzing, improving, and reexamining the total testing
process
Quality assurance
Quality control limits derived from
clinical application of results rather than statistical
imprecision of the method
Medical usefulness limits
An error that is always in one
direction and whose magnitude is a percentage of the concentration of analyte being measured
Proportional systematic error
Arithmetic average of a set of values.
Mean
