Quality Control Flashcards
To have value for clinical decision-making, what condition must be met by the laboratory result?
it must have a total error small enough to reflect the biological condition being evaluated
A. Pre-analytical variability in sample collection, transportation, processing and storage
B. Analytical variability in test performance
C. Interfering substances such as drugs or metabolic components
D. Disposition of the patient
Which does not affect the total error of the result?
D
Which post-analytical variable may affect result’s total error?
A. incorrect reference values
B. incorrect label of result
C. incorrect interpretation of lab results by physician
D. Incorrect data entry of lab result
B
identify type of error
A. Precise and inaccurate
B. Systematic change in the test system resulting in the displacement of the mean from the original value
C. Predictable and causes shifts or trends on control charts that are consistently low or high
systematic error
Which does not cause systematic error?
A. Variation in sample or reagent volumes due to pipettor
misalignments
B. Variation in temperature or reaction chambers
C. Deterioration of photometric light source
D. Air bubbles in reagent
D
D causes random error
Which does not cause random error? A. Improperly fitting pipette tips B. Improperly prepared reagent C. Clogged or imprecise pipette D. Fluctuations in power supply
B
In quality control, what is bias?
the amount by which an analysis varies from the
correct result
the __ the coefficient of variation, the more reproducible the
results since more values are closer to the mean
A. smaller
B. bigger
C. it does not matter
A
measure of dispersion that is more useful in comparing 2 or more analytical methods
A. standard deviation
B. coefficient of variation
C. same lang
B
False about calibration
A. establishes precision
B. can reduce the systematic bias to zero
C. individual patient that results from a correctly
calibrated method will have variability consistent with
the inherent imprecision of the method
A
identify: A process to statistically sample a measurement
procedure to verify if it is performing according to preestablished
specifications
quality control
false about selection of QC materials
A. 2 different concentrations: normal or high/low
B. QC Material should approximate the same matrix* as patient specimens
C. minimal vial to vial variability
D. stable for long periods of time
E.. Lyophilized controls (powder) are more convenient than liquid controls
E
liquid: mas convenient. less pipetting error
A QC matl must have minimal vial to vial variability because ___
variability could be misinterpreted as systematic error in the method or instrument
How often do we run QC materials depends on all of the ff, except:
A. The analytical stability of the method
B. Amount of last sample during the shift
C. The number of patient samples measured in a period of time
D. The need to verify and document the reliability of clinical results at the time they are reported
B
___ is a material or preparation used to verify the analytic measurement range of instrument for a specific analyte
Control
