, TEST BANK For Current Medical
Diagnosis And Treatment 2024, 63rd
Edition By Maxine Papadakis, Stephen
Mcphee, Verified Chapters 1 - 42,
Complete Newest Version.
A recent study of different measures of left ventricular function gave
the following results for mean values in the (healthy) study group:
Mean ejection fraction 59%, mean systolic shortening of the left
ventricle: 17 mm, mean systolic tissue velocity: 9.1 cm/s and mean
systolic strain rate (shortening velocity per length unit) -1.1 s-1 To
compare the usefulness of the different measures, we look at the
reproducibility of the results, doing repeated measurements. Which
measure of repeatability would be best here for comparison of the
accuracy of the different measures?
A) Limits of agreement
B) Correlation
C) Mean error
D) kappa coefficient - ANSWER -C) Mean error
Ejection fraction measured by ultrasound has a high variability. Limits of
agreement are ± 10% points. A patient who has had an infarct had an
ejection fraction of 45% (slightly reduced) when he left the hospital.
Two months later, he was admitted because of dyspnea, but had no
new infarction. During the second stay, a new echocardiography was
pg. 2
,made, and they now found an EF of 38%. The diagnosis of worsening
heart failure (HF) was made, and medical treatment for heart failure
was started. The conclusion that the patient had worsening heart failure
was:
a) Correct because the EF was below 40%
b) Correct because the EF had dropped by 7% points
c) Incorrect because a change of 7% points is not a significant change
with this method
d) Incorrect because an EF of 38% is not compatible with heart failure. -
ANSWER -c) Incorrect because a change of 7% points is not a significant
change with this method
Ejection fraction measured by ultrasound has a high variability. Limits of
agreement are ± 10% points. A patient who has had an infarct had an
ejection fraction of 48% (slightly reduced) when he left the hospital.
Two months later, he was admitted because of dyspnea, but had no
new infarction. During the second stay, a new echocardiography was
made, and they now found an EF of 35%. The diagnosis of worsening
heart failure (HF) was made, and medical treatment for heart failure
was started. The conclusion that the patient had worsening heart failure
was:
A) Correct because the EF was below 40%
B) Correct because the EF had dropped by 13% points
C) Incorrect because a change of 13% points is not a significant change
with this method
D) Incorrect because an EF of 35% is not compatible with heart failure. -
ANSWER -B) Correct because the EF had dropped by 13% points
pg. 3
, What is the sensitivity of a certain diagnostic test?
A) The probability of having a positive test if you are ill
B) The probability of having a negative test if you are healthy
C) The probability of being ill if you have a positive test
D) The probability of being healthy if you have a negative test -
ANSWER -A) The probability of having a positive test if you are ill
What do we mean by the positive predictive value of a test:
A) The probability of being ill if the test shows the patient to be ill
B) The probability of being healthy, if the test shows the patient to be
healthy
C) The probability of being ill, despite the test showing the patient to be
healthy
D) The probability of being healthy, despite the test showing the patient
to be ill - ANSWER -A) The probability of being ill if the test shows the
patient to be ill
The usefulness of a diagnostic test is dependent on it's ability to
separate a healthy population from the population with the disease
that the test is specific for. Validity is the bias of the test measure from
the "truth". Reliability or precision is the statistical spread of repeated
measurements. Which factor is most important for the diagnostic
usefulness?
A) The validity of the test
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