Quality Assessment
Quality Assurance
Quality Management correct answers Process that includes a set of activities that aids in improving the reliability of the laboratory
Quality Control correct answers Falls under quality assurance. Monitors analytical aspects of a method, verifying that re...
Quality Assessment
Quality Assurance
Quality Management correct answers Process that includes a set of activities that aids
in improving the reliability of the laboratory
Quality Control correct answers Falls under quality assurance. Monitors analytical
aspects of a method, verifying that results from a given method are precise and
accurate. Monitors performance of lab instruments, reagents, other testing products and
equipment, technical error by personnel
Accuracy correct answers Correctness
How closely a measured value agrees with a true or expected value. Occurs when
control results consistently fall within 1 SD of the mean. Concerned with sensitivity and
specificity
Precision correct answers Reproducibility of a test system. Ability to produce the same
test result each time. Detects random error of the method. Used to define the
acceptable range.
Mean correct answers x with a line over it. A mathematical average, calculated by
dividing the sum of all individual values by the number of values
Mode correct answers Value that occurs most commonly in a group of data
Median correct answers Middle value of a body of data. If all variables are arranged in
order of increasing magnitude, the median is that variable which falls halfway between
the highest and the lowest
Standard Deviation correct answers Statistic that describes the distribution of all values
around the mean for a particular group. Used to test precision
Standard Deviation Index correct answers Describes the number of standard deviations
away from the mean that a result is
Coefficient of Variation (CV) correct answers Used to compare the
Shift correct answers Sudden and sustained change in quality control results above or
below the mean, then continues at the same level
, Would recent calibrations, a new shipment of control, or a new lot of calibrator be more
likely to cause a shift or trend in data? correct answers shift
Trend correct answers Gradual but steady change in QC results. Moving up or down
away from the mean
Would aging controls or reagents, needed maintenance, or a fading light source be
more likely to cause a shift or trend in data? correct answers trend
Reference Range correct answers Reference point to determine whether a disease is
present or absent, or if a patient is at risk for future disease states. Range of values for
a given analyte in a defined population. Derived from a group of "normal and healthy"
individuals. Measurements will statistically follow the normal Gaussian distribution of
data. Includes 95% of test results
Bias correct answers Observed result minus the assigned value. Difference between
results from the reference method (current) and results from a method under
investigation (new)
Reliability correct answers The result when BOTH accuracy and precision are
accomplished
Variance correct answers Factors or fluctuations that affect the measurement of the
substance in question. The ERROR of a procedure
Random Error correct answers Error that occurs unpredictably due to poor precision.
Identified by a sudden fluctuation in the QC measurement, either above or below the
mean.
Reagent dispensing, sample evaporation, temperature of analyzer, optical system,
calibrator reconstitution, environmental conditions, instability of instrument, variation in
specimen handling techniques, variation in operators are all examples of what kind of
error? correct answers Random Error
Systematic Error correct answers Recurring error that affects all results. Can be
identified by a trend in QC measurement.
Aging reagents or calibrators, instrument components, optical changes, fluctuations in
voltage, wear and tear of instrument, reagent lot variability, calibration differences,
technologist interactions are all examples of what kind of error? correct answers
Systematic Error
Type I QC Error correct answers Rejecting a control when it should be accepted
Type II QC Error correct answers Accepting a control when it should be rejected
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