TEST BANK For Tietz Fundamentals of Clinical Chemistry and
Molecular Diagnostics, 8th Edition by Nader Rifai,
true negatives / (false positives + true negatives) is the formula for determining: -
ANSWER:specificity
The proportion of a population that has the particular disease being studied is
referred to as the: - ANSWER:Prevalence
What is the positive predictive value of a test in which 220 individuals with positive
test results actually have the disease and 45 individuals with positive test rates do
not have the disease? - ANSWER:83%. 220/(220+45)
In regard to the number of true-positive and negative, and false-positive and
negative, results in laboratory testing the prevalence times the sensitivity is equal to
the number of: - ANSWER:True positives
Calculate the sensitivity for the following data: in a group of 80 patients diagnosed
with sickle cell disease, 72 tested positively for it. The sensitivity of this test is: -
ANSWER:72/(72+8) * 100 = 90%
A receiver operating characteristic (ROC) curve is a plot of: - ANSWER:True positives
versus false positives
ROC curves are most useful in assessing the performance of quantitative laboratory
analysis because: - ANSWER:They can display performance of tests over the entire
range of decision values
A laboratory analysis that produces quantitative results with an infinite number of
sensitivity and specificity pairs is referred to as a _________ test. -
ANSWER:Continuous
Non-diseased individuals that are classified as diseased by having a positive result on
a specific laboratory test are considered: - ANSWER:False positive
Combination testing involves the use of multiple laboratory tests in an attempt to
decrease costs or assist in diagnosing a specific disease. One of the problems with
this type of testing is that: - ANSWER:False-positive results increase
A method that can be used to calculate the probability of a disease after new
information is added to previously obtained information involves: - ANSWER:Bayes
theorem
To calculate the sensitivity of a laboratory test to correctly classify true positives, one
must first know the number of: - ANSWER:True positives and false negatives
, To calculate the predictive value of a positive test, which of the following should be
known? - ANSWER:sensitivity, specificity, and prevalence
The probability of occurrence of a specific test value given that the disease is present
divided by the probability of the same test value if the disease was absent is the: -
ANSWER:likelihood ratio
In regard to clinical evaluation of method, a high clinical sensitivity means few false
negatives. - ANSWER:True
Even in somewhat impractical, which one of the following pre-analytical factors
should be standardized when establishing a reference interval for an analyze? -
ANSWER:The method of specimen collection
To determine the confidence intervals of percentiles of ranked data (data arranged
by magnitude of value), it is most appropriately assessed using: -
ANSWER:Nonparametric testing
True negatives / (false positives + true negatives) * 100 is the formula for
determining: - ANSWER:Clinical specificity
Calculate the clinical sensitivity for the following data: in a group of 80 patients
diagnosed with sickle cell disease, 72 had positive test results. The clinical sensitivity
of the test is: - ANSWER:72/80 * 100 = 90%
Which one of the following is an example of an exclusion criterion when establishing
a healthy population-based reference interval? - ANSWER:Use of oral contraceptives
An important assumption that is made when using parametric methods to estimate
percentiles and their confidence intervals in determining reference limits is that: -
ANSWER:the true distribution that the reference values exhibit is Gaussian
A physician asked your laboratory to being performing thyroid-stimulating hormone
(TSH) analyses on all specimens that have a free thyroxine (FT4) analysis ordered, a
practice that your laboratory currently does not perform. Your laboratory typically
performs TSH only on these FT4 specimens that are outside the population-based
reference interval. The physician suggests using subject-based reference intervals,
claiming that population-based intervals are clinically insensitive. What is the basis of
the claim? - ANSWER:Changes in a subject-based reference value might indicate
altered biochemical status yet still be within the population-based healthy reference
interval.
What the statistical range of the following distribution of the data?
21 25 18 20 19 21 23 26 - ANSWER:8
Molecular Diagnostics, 8th Edition by Nader Rifai,
true negatives / (false positives + true negatives) is the formula for determining: -
ANSWER:specificity
The proportion of a population that has the particular disease being studied is
referred to as the: - ANSWER:Prevalence
What is the positive predictive value of a test in which 220 individuals with positive
test results actually have the disease and 45 individuals with positive test rates do
not have the disease? - ANSWER:83%. 220/(220+45)
In regard to the number of true-positive and negative, and false-positive and
negative, results in laboratory testing the prevalence times the sensitivity is equal to
the number of: - ANSWER:True positives
Calculate the sensitivity for the following data: in a group of 80 patients diagnosed
with sickle cell disease, 72 tested positively for it. The sensitivity of this test is: -
ANSWER:72/(72+8) * 100 = 90%
A receiver operating characteristic (ROC) curve is a plot of: - ANSWER:True positives
versus false positives
ROC curves are most useful in assessing the performance of quantitative laboratory
analysis because: - ANSWER:They can display performance of tests over the entire
range of decision values
A laboratory analysis that produces quantitative results with an infinite number of
sensitivity and specificity pairs is referred to as a _________ test. -
ANSWER:Continuous
Non-diseased individuals that are classified as diseased by having a positive result on
a specific laboratory test are considered: - ANSWER:False positive
Combination testing involves the use of multiple laboratory tests in an attempt to
decrease costs or assist in diagnosing a specific disease. One of the problems with
this type of testing is that: - ANSWER:False-positive results increase
A method that can be used to calculate the probability of a disease after new
information is added to previously obtained information involves: - ANSWER:Bayes
theorem
To calculate the sensitivity of a laboratory test to correctly classify true positives, one
must first know the number of: - ANSWER:True positives and false negatives
, To calculate the predictive value of a positive test, which of the following should be
known? - ANSWER:sensitivity, specificity, and prevalence
The probability of occurrence of a specific test value given that the disease is present
divided by the probability of the same test value if the disease was absent is the: -
ANSWER:likelihood ratio
In regard to clinical evaluation of method, a high clinical sensitivity means few false
negatives. - ANSWER:True
Even in somewhat impractical, which one of the following pre-analytical factors
should be standardized when establishing a reference interval for an analyze? -
ANSWER:The method of specimen collection
To determine the confidence intervals of percentiles of ranked data (data arranged
by magnitude of value), it is most appropriately assessed using: -
ANSWER:Nonparametric testing
True negatives / (false positives + true negatives) * 100 is the formula for
determining: - ANSWER:Clinical specificity
Calculate the clinical sensitivity for the following data: in a group of 80 patients
diagnosed with sickle cell disease, 72 had positive test results. The clinical sensitivity
of the test is: - ANSWER:72/80 * 100 = 90%
Which one of the following is an example of an exclusion criterion when establishing
a healthy population-based reference interval? - ANSWER:Use of oral contraceptives
An important assumption that is made when using parametric methods to estimate
percentiles and their confidence intervals in determining reference limits is that: -
ANSWER:the true distribution that the reference values exhibit is Gaussian
A physician asked your laboratory to being performing thyroid-stimulating hormone
(TSH) analyses on all specimens that have a free thyroxine (FT4) analysis ordered, a
practice that your laboratory currently does not perform. Your laboratory typically
performs TSH only on these FT4 specimens that are outside the population-based
reference interval. The physician suggests using subject-based reference intervals,
claiming that population-based intervals are clinically insensitive. What is the basis of
the claim? - ANSWER:Changes in a subject-based reference value might indicate
altered biochemical status yet still be within the population-based healthy reference
interval.
What the statistical range of the following distribution of the data?
21 25 18 20 19 21 23 26 - ANSWER:8
