QUALITY CONTROL Flashcards
(22 cards)
all are characteristics of quality control, except:
a. system of ensuring accuracy and precision in the laboratory by including quality control reagents in every series of measurements.
b. process of ensuring that analytical results are correct by testing known samples that resemble patient samples
c. it involves the process of monitoring the characteristics of the analytical processes and detects analytical errors during testing
d. part of quality assurance system
e. nota
e. nota
the ability of an analytical method to measure the smallest concentration of the analyte of interest
sensitivity
the ability of an analytical method to measure only the analyte of interest
specificity
the nearness of closeness of the assayed value to the true or target value
accuracy
the ability of an analytical method to give repeated results on the same sample that agree with one another
precision/reproducibility
the degree by which a method is easily repeated
practicability
the ability of an analytical method to maintain accuracy and precision over an extended period of time during which equipment, reagents, and personnel may change
reliability
is the ability of the test to detect the proportion of individuals with that disease who test positive with the test
diagnostic sensitivity
other name for diagnostic sensitivity
true positive
% sensitivity formula
(number of diseased individuals with positive test/total number of diseased individuals tested) x 100
is the ability of the test to detect the proportion of individuals without the disease who test negatively for the disease
diagnostic specificity
other name for diagnostic specificity
true negative
% specificity formula
(number of individuals without the disease with a negative test/total number of individuals without the disease) x 100
kind of quality control:
-involves the analyses of control samples together with the patient specimens
-detects changes in performance between the present operation and the stable operation
-important for daily monitoring
-detects both random and systematic errors
intralab (internal QC)
what QC parameter is being checked in intralab (internal QC)?
precision
kind of quality control:
-involves the proficiency testing programs that periodically provide samples of unknown concentration of analytes to participating laboratories
-it is important in maintaining long-term accuracy of the analytical methods
-used to determine estimates of the state-of-the-art interlaboratory performance
interlab (external QC)
value that indicates that the laboratory is not in agreement with the rest of the laboratories in external QC
difference of > 2
characteristics of ideal QC material
characteristics of ideal QC material (6)
- resembles human sample
- inexpensive and stable for long periods
- no communicable diseases
- no matrix effects
- with known analyte concentrations
- convenient packaging for easy dispensing and storage
true or false. human control materials are preferred without exceptions
false. human control materials are preferred but because of limited sources and biohazard considerations, bovine control materials are used.
bovine-based qc material is not the choice for: (3)
immunochemistry
dye-binding
bilirubin assays
results of improper product manufacturing, use of unpurified human and nonhuman analyte additives and altered protein components
matrix effects
