Errors in Quality Control Training
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ERRORS
(SYSTEMATIC Vs RANDOM
)
Labs for Life Project
QUALITY CONTROL TRAINING
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Errors
Accuracy and Precision
Inaccurate but
Precise
Inaccurate
and Imprecise
Accurate and
Accurate and
Precise
Precise
BIAS
SD
Let us examine inaccuracies first.
We have looked at the rules that indicate shifting accuracies
We have seen that shifting accuracies are denoted by shifting means
We have seen that inaccuracies are indicated by bias in the LJ graphs.
Before we go to the changes in the analytical system that produces
these errors, we have to understand the kinds of systematic errors that
can happen
Types of Systematic Errors
Shifts Trend
Shift:
Systematic Error
Shift: Abrupt changes in the
control mean
a sudden and dramatic
positive or negative
change in test system
performance
.
Causes for Shifts: Sudden Changes/
Failures
Light
Reagent Formulation
Major Instrument Maintenance
Incubation temperature
(enzymes)
Room Temperature
Failure in the sampling
system/reagent dispensing
change in reagent formulation
reagent lot
major Instrument maintenance / change in room temperature or humidity
Failure in the sampling system/reagent dispense/inaccurate calibration or recalibration
Trend:
Systematic error
Trend :gradual loss of reliability in the test system
Cause
:
Deterioration of the instrument light source
Gradual accumulation of debris in sample /reagent tubing
Aging of reagents
Gradual deterioration of control materials
Gradual deterioration of incubation chamber temperature(enzymes
only)
Gradual deterioration of calibration
Recap…..
Random ERROR: Imprecision
Precision
is the amount of
variation in the measurements, a
random deviation away from an
expected result (computed as
Random Error;
to be discussed later
)
REASONS
Improperly mixed /dissolved reagents
Air bubbles in reagents and reagents lines, sampling or reagents
syringes.
Pipette tips is not fitting properly.
A clogged pipettor (Clot).
Unstable temperature and incubation.
Unstable power supply.
Poor operator technique.
Improper mixing of processed samples.
Incorrect reconstitution of the control material.
Thanks
Explore the difference between systematic and random errors in labs, focusing on accuracy and precision. Learn about types of systematic errors such as shifts and trends, their causes, and how they affect the reliability of test systems. Discover the impact of random errors on precision and variability in measurements.
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Presentation Transcript
ERRORS (SYSTEMATIC Vs RANDOM) Labs for Life Project QUALITY CONTROL TRAINING
Accuracy and Precision Inaccurate but Precise Inaccurate and Imprecise SD BIAS BIAS Accurate and Precise
Let us examine inaccuracies first. We have looked at the rules that indicate shifting accuracies We have seen that shifting accuracies are denoted by shifting means We have seen that inaccuracies are indicated by bias in the LJ graphs. Before we go to the changes in the analytical system that produces these errors, we have to understand the kinds of systematic errors that can happen
Types of Systematic Errors Shifts Trend
Shift: Systematic Error Shift: Abrupt changes in the control mean a sudden positive or negative change in performance. and dramatic test system
Causes for Shifts: Sudden Changes/ Failures Light Reagent Formulation Major Instrument Maintenance Incubation temperature (enzymes) Room Temperature Failure in the sampling system/reagent dispensing
Trend: Systematic error Trend :gradual loss of reliability in the test system Cause : Deterioration of the instrument light source Gradual accumulation of debris in sample /reagent tubing Aging of reagents Gradual deterioration of control materials Gradual deterioration of incubation chamber temperature(enzymes only) Gradual deterioration of calibration
Random ERROR: Imprecision Precision is the amount of variation in the measurements, a random deviation away from an expected result (computed as Random Error; to be discussed later)
REASONS Improperly mixed /dissolved reagents Air bubbles in reagents and reagents lines, sampling or reagents syringes. Pipette tips is not fitting properly. A clogged pipettor (Clot). Unstable temperature and incubation. Unstable power supply. Poor operator technique. Improper mixing of processed samples. Incorrect reconstitution of the control material.
