Chapter 34: Quality Assurance Flashcards
the overall percentage of correct results
accuracy
a well-established and reliable testing parameter, which, for vascular disease, is often angiography
gold standard
the evaluation of one’s work by other experts in the same field
peer review
it is the ability of a test to detect disease
sensitivity
it is the ability of a test to correctly identify a normal result
specificity
a program for the systematic monitoring and evaluation of the various aspects of vascular testing to ensure that standards of quality are met
quality assurance
making effective use of numerical data relating to groups of individuals or experiments
statistics
compare one form of a diagnostic test with another that is well-established, reliable, and considered reference standard
“gold standard”
assumed to be the truth
“gold standard”
number of studies performed which state disease is present and gold standard agrees
true positives
number of negative findings reported that were also reported negative by gold standard
true negatives
studies that are reported positive but found to be negative by the gold standard
false positives
states that a study is normal when gold standard identifies disease
false negatives
the degree of “closeness” something is to its actual value
accuracy
percentage of correct results
accuracy
calculated as total number of correct tests divided by the total number of all tests
accuracy
measures the proportion of actual positives studies correctly identified
sensitivity
ability to identify disease when disease is present
sensitivity
calculated by taking TP results and dividing by all positive results determined by gold standard
sensitivity
ability of a test to identify something as normal or the absence of disease
specificity
calculated by dividing the number of TN results by all the negative results as identified by gold standard
specificity
consistency of obtaining similiar results in similar circumstances
reliability
accuracy over a period of time
reliability
proportion of patients with positive test results that are correctly identified
positive predictive value
provides probability that positive test reflects underlying disease for which the test is being conducted
positive predictive value
calculated at the number of TP studies divided by all the positive studies
positive predictive value
The proportion of negative test results when there is no underlying disease present
negative predictive value
provides probability that a negative test reflects absence of diseaes
negative predictive value
statistical test, that in sum, compares the difference between what one “expects” and what one actually “observes”
the chi-square test
the more test that are performed that agree with the “gold standard” or the narrower the difference between what is expected and what is observed, the greater the accuracy
the chi-square test
table containing four letters (A, B, C, and D); each letter represents the results of what was expected and what was observed
the chi-square test
duplex ultrasound is what was ______
expected
angiogram is what was _____
observed
offers a well established alternative method of QA
Peer review
specific quality indicators for peer review
test appropriateness
adherence to criteria
technical quality
adherence to protocol
completeness
timeliness
______ values are an integral part of a QA program.
statistical
In vascular testing, what is typically considered to be the gold standard?
angiography
What is the identification of a 50% - 70% stenosis of the internal carotid artery and a 60% stenosis by angiography an example of?
true positive
Upon ultrasound evaluation, DVT is found in the popliteal vein; venography demonstrates a widely patent vessel. What is this an example of
false positive
During duplex assessment of the abdominal aorta, the aorta measures less than 2.0 cm, which is confirmed by angiography. What is this an example of?
true negative
Duplex evaluation of the superior mesenteric artery demonstrated velocities of 150 cm/s. Angiography demonstrated a 70% stenosis in the same vessel. What is this an example of?
false negative
Which of the following is NOT likely to occur if false-positive results are indicated by the duplex ultrasound examination?
a. unnecessary treatment
b. lack of treatment when treatment is needed
c. unnecessary stress to the patient
d. repeat examination
a
Which of the following would have the highest accuracy?
a. 25 true positives and 30 true negatives out of 100 examinations
b. 20 true positives and 10 true negatives out of 100 examinations
c. 50 true positives and 5 true negatives out of 100 examinations
d. 10 true positives and 75 true negatives out of 100 examinations
d
An increase in which of the following results would increase the sensitivity of an examination?
a. false positive
b. false negative
c. true positive
d. true negative
c
Which results are needed to improve specificity?
a. true negatives
b. true positives
c. false negatives
d. false positives
a
What is the consistency of obtaining similar results under similar circumstances?
reliability
Which of the following would an increase in the number of false-positive results have impact on?
a. positive predictive value and negative predictive value
b. positive predictive value and specificity
c. negative predictive value and sensitivity
d. positive predictive value and sensitivity
b
After statistical analysis, a test was found to have a sensitivity of 92% and a specificity of 84%. Which of the following could represent the overall accuracy?
a. 95%
b. 82%
c. 89%
d. cannot be determined
c
If a test has a negative predictive value of 50%, how sure can you be that your test results is negative?
equivocal
In general, if the sensitivity of a test increases, what will happen to the specificity of the test?
decreasese
Which of the following parameters would an increase in the number of false-negative results impact?
a. negative predictive value and sensitivity
b. positive predictive value and sensitivity
c. sensitivity and specificity
d. negative predictive value and specificity
a
_________ refers to a program for the systematic monitoring and evaluation of the various aspects of vascular testing to ensure that standards of quality are being met.
quality assurance
_______ is the science of making effective use of numerical data relating to groups of individuals or experiments
statistics
A(n) ______ is used to compare one form of a newer diagnostic test with another that is well established and reliable.
gold standard
_______ are the number of studies performed by ultrasound, which state that disease is present and the gold standard agrees with the ultrasound findings.
true positives
_______ are the number of studies performed by ultrasound, which state that disease is not present and are also reported as negative by the gold standard.
true negatives
Studies that are reported positive by ultrasound but are found to be negative by the gold standard are known as
false positives
If a study is normal on ultrasound but the gold standard identifies disease, it is an example of a(n) _____
false negative
Accuracy is calculated as ______ number of correct tests _____ by the total number of all tests.
total
divided
_____ is calculated by taking the true positive results and dividing these by all positive results as determined by the gold standard
sensitivity
Dividing the number of true negatives by all the negative results as identified by the gold standard results in the ______ of the test.
specificity
A vascular laboratory that has an overall accuracy of 96% over an average of 5 years would be said to be ______
reliable
_______ is calculated as the number of true positives divided by all the positive studies
positive predictive values
True negatives divided by all studies determined to be negative results in the _______
negative predictive value
In a chi-square analysis, boxes A and B are used to determine ______, whereas boxes C and D are used to determine ____.
positive predictive value
negative predictive value
In a chi-square analysis, boxes A and C are used to determine ______, whereas boxes B and D are used to determine _____.
sensitivity
specificity