TEST BANK FOR TIETZ FUNDAMENTALS OF CLINICAL CHEMISTRY AND MOLECULAR DIAGNOSTICS 7TH EDITION BY BURTIS
Table of Contents
Chapter 01: Clinical Chemistry,
... [Show More] Molecular Diagnostics, and Laboratory Medicine .................... 1 Chapter 02: Selection and Analytical Evaluation of Methods With Statistical Techniques ............. 5 Chapter 03: Clinical Evaluation of Methods ................................ ................... 11 Chapter 04: Evidence-Based Laboratory Medicine ................................ .............. 13 Chapter 05: Establishment and Use of Reference Values ................................ ......... 16 Chapter 06: Specimen Collection, Processing, and Other Preanalytical Variables ..................... 18 Chapter 07: Quality Management ................................ ........................... 21 Chapter 08: Principles of Basic Techniques and Laboratory Safety ................................ . 25 Chapter 09: Optical Techniques ................................ ............................. 28 Chapter 10: Electrochemistry and Chemical Sensors ................................ ........... 32 Chapter 11: Electrophoresis ................................ ................................ 35 Chapter 12: Chromatography ................................ ............................... 37 Chapter 13: Mass Spectrometry ................................ ............................. 41 Chapter 14: Enzyme and Rate Analyses ................................ ...................... 43 Chapter 15: Immunochemical Techniques ................................ .................... 47 Chapter 16: Automation ................................ ................................ ... 50 Chapter 18: Amino Acids, Peptides, and Proteins ................................ ............... 53 Chapter 19: Serum Enzymes ................................ ............................... 57
Chapter 01: Clinical Chemistry, Molecular Diagnostics, and Laboratory Medicine 1 | P a g eMULTIPLE CHOICE
1. An individual working in a clinical chemistry laboratory is married to a sales representative
who works for a company that sells chemistry laboratory supplies. When the laboratory
manager requests a list of needed supplies, cost of supplies, and vendors, this individual only
recommends the spouse’s company as the vendor. This is considered to be a(n):
a. accounting issue.
b. possible conflict of interest.
c. maintenance of confidentiality issue.
d. problem with resource allocation.
ANS: B
Concern has been raised over the interrelationships between practitioners in the medical field
and commercial suppliers of drugs, devices, equipment, etc., to the medical profession.
Similarly, relationships have been scrutinized between clinical laboratorians and
manufacturers and providers of diagnostic equipment and supplies. These concerns led the
National Institutes of Health (NIH) in 1995 to require official institutional review of financial
disclosure by researchers and management of situations in which disclosure indicates potential
conflicts of interest.
DIF: 1
REF: Page 4-5
OBJ: 6 | 7
2. A patient visits her physician stating that her prescribed painkiller is not working to reduce the
pain following her recent surgery. A friend of the patient claims that the same painkiller
“worked wonders” to reduce her pain after the same surgery. The physician states that the
difference in the effect of the drug might be caused by
, which is studied in
pharmacogenetics.
a. epidemiology
b. an inherited disease
c. a conflict of interest
d. a genetic variation in drug-metabolizing enzymes
ANS: D
Pharmacogenetics is the study of the genetic variation of drug metabolism between
individuals.
DIF: 1
REF: Page 3
OBJ: 1
3. John works in a molecular diagnostics laboratory and receives a blood sample that has the
name of a close friend printed on the bar-coded label. The genetic test that is ordered on the
friend’s sample would provide diagnostic information about a disorder that has a poor
prognosis, and the test is usually performed by John. He asks a fellow employee to analyze
the sample for him and not divulge the results. This ethical issue concerns:
a. confidentiality of patient genetic and medical information.
b. a conflict of interest.
c. resource allocation.
d. diagnostic accuracy.
ANS: A
Clinical laboratorians have long been responsible for maintaining the confidentiality of all
laboratory results, a situation made even more critical with the advent of increasingly
powerful genetic testing.
2 | P a g eDIF: 1
REF: Page 4
OBJ: 6 | 7
4. Molecular diagnostic testing methods and results can be:
a. qualitative only.
b. quantitative only.
c. either qualitative or quantitative.
ANS: C
Molecular diagnostic methods can be either qualitative or quantitative in nature, depending on
the clinical need.
DIF: 1
REF: Page 3
OBJ: 5
5. Clinical epidemiology, which is the study of the patterns, causes, and effects of health and
disease in certain populations, has provided the clinical laboratory with methods that evaluate
the effects and outcomes of laboratory testing. This allows for a more effective:
a. process of determining the cost of the testing methods.
b. selection and interpretation of laboratory tests.
c. determination of the boundaries between the components of the clinical lab.
d. conduct assessment.
ANS: A
Clinical epidemiologists have introduced methods to evaluate the effects and value of
laboratory testing in healthcare. These developments are expected to play an increasing role in
the selection and interpretation of laboratory tests.
DIF: 1
REF: Page 3
OBJ: 4
6. Analysis of which one of the following by molecular diagnostic methods provides a measure
of processes that are ongoing at the time of blood sampling?
a. Genetic variation in an individual’s response to a drug
b. Circulating plasma nucleic acids
c. Malignant lymphomas
d. Histocompatibility
ANS: B
Molecular diagnostics, given its very high sensitivity, has been applied to the study of plasma
nucleic acids (or circulating nucleic acids). Plasma nucleic acids analysis has been made
possible by the discovery that dying cells in the body release their DNA and RNA into the
extracellular compartment and ultimately into the bloodstream, where they can be detected
and analyzed. Given their short half-life in circulation (less than 24 hours), plasma nucleic
acids provide a measure of processes that are ongoing at the time of blood sampling.
DIF: 1
REF: Page 3
OBJ: 5
7. A healthy individual with no clinical signs or symptoms of disease visits his physician for a
routine physical examination. Blood samples are collected and sent to the laboratory. The tests
requested on the sample are for general laboratory analyses, including a complete blood count,
a panel of general chemistry tests (including glucose, protein, cholesterol, and others), and an
analysis of urine. This type of testing in laboratory medicine is directed at:
a. confirming a clinical suspicion of disease.
b. selecting a treatment for disease.
c. ruling in a diagnosis.
d. screening for disease in the absence of clinical signs or symptoms.
3 | P a g eANS: D
Testing in laboratory medicine may be directed at (1) confirming a clinical suspicion; (2)
making, or ruling in, a diagnosis; (3) excluding, or ruling out, a diagnosis;, (4) assisting in the
selection, optimization, and monitoring of treatment; (5) providing a prognosis; (6) screening for
disease in the absence of clinical signs or symptoms; or (7) establishing and monitoring the
severity of a physiologic disturbance. The field of laboratory medicine includes clinical
chemistry and areas such as microbiology and hematology. The general tests ordered on this
healthy individual are done to screen the physiologic systems despite the absence of any
symptoms.
DIF: 2
REF: Page 2
OBJ: 2
8. The discipline involved in the selection, provision, and interpretation of diagnostic testing that
uses primarily samples from patients is:
a. clinical chemistry.
b. hematology.
c. laboratory medicine.
d. molecular diagnostics.
ANS: C
The term “laboratory medicine” refers to the discipline involved in the (1) selection, (2)
provision, and (3) interpretation of diagnostic testing that uses primarily samples from
patients.
DIF: 1
REF: Page 1
OBJ: 1 | 3
9. A male laboratorian works in the clinical chemistry laboratory of a large hospital. He is
approached by his friend, who is a representative of a drug company, and asked to analyze
some patient samples for drug levels of a specific drug that the representative’s company sells
and that these patients use. The representative wants to publish a report on the rate of drug
absorption and distribution of this drug and tells his laboratorian friend that he will
personally reimburse him for his time. What ethical issues come into play here?
a. Resource allocation and conflict of interest
b. Maintenance of confidentiality and publishing issues
c. Maintenance of confidentiality, conflict of interest, and publishing issues.
d. Resource allocation, maintenance of confidentiality, conflict of interest, and
publishing issues.
ANS: D
Resource allocation, maintenance of confidentiality, conflict of interest, and publishing issues
are being compromised by the representative and the laboratorian if the laboratorian follows
through with the request. Using laboratory resources for a study that has not been approved
by the institutional review board is a resource allocation issue, revealing results of laboratory
tests is a confidentiality issue, receiving money to run laboratory tests from an individual with
a direct interest in the laboratory results is a conflict of interest, and publishing the results of
the testing would possibly be considered fraudulent and inappropriate.
DIF: 2
REF: Page 4-5
OBJ: 3 | 6 | 7
TRUE/FALSE
1. Molecular diagnostics testing is only used by the clinical chemistry laboratory.
ANS: F
4 | P a g eThe discipline of molecular diagnostics, which entered the realm of laboratory medicine in
multiple forms and in multiple fields, includes but is not limited to the study of hematopoietic
malignancies, such as malignant lymphomas and leukemias; the existence of nonhost nucleic
acids (microorganisms, graft-donor, fetal nucleic acids during pregnancy); and assessment of
solid tumors.
DIF: 1
REF: Page 3
OBJ: 1 | 5
Chapter 02: Selection and Analytical Evaluation of Methods With Statistical
Techniques
MULTIPLE CHOICE
1. A statistic is a:
a. constant that describes some particular characteristic of a population.
b. value calculated from the observations in a sample to describe a particular
characteristic of that sample.
c. complete set of all observations that might occur as a result of performing a
particular procedure according to specified conditions.
d. graphic device for displaying a large set of data.
ANS: B
A statistic is a descriptive measure of a sample; it is a value calculated from the observations
in a sample to describe a particular characteristic of that sample.
DIF: 1
REF: Page 10
OBJ: 3
2. A population mean (µ) is calculated by which one of the following formulae?
a.
xi/N
b. (b 1)/SE(b)
c. (x2i x1i)
d. (x1
)2/N
ANS: A
The parameter most commonly used to describe the central location of a population of N
values is the population mean ( ):
DIF: 1
REF: Page 10
OBJ: 3 | 11
3. Which one of the following is the correct formula for calculating the percent coefficient of
variation of a set of measurements?
a. CV = standard deviation 100%
b. CV = standard deviation ÷ 100%
c. CV = (standard deviation ÷ mean) 100%
d. CV = (mean + standard deviation) ÷ 100%
ANS: C
The coefficient of variation is the measure of relative imprecision. The value of CV% is
5 | P a g edetermined by calculating the ratio of the SD to the mean multiplied by 100%.
DIF: 1
REF: Page 10
OBJ: 11
4. The type of method comparison that compares the average results between two analyses with
the differences between varying concentration values of the two analyses is referred to as a(n):
a. Deming analysis.
b. linear regression plot.
c. ordinary least-squares plot.
d. Bland-Altman difference plot.
ANS: D
When comparing values obtained with two different methodologies, the average values of the
results are plotted against the differences between the values obtained from the two methods.
This examines the differences at varying analyte concentrations to determine whether a
problem exists at a certain concentration.
DIF: 2
REF: Page 19
OBJ: 1 | 6
5. How is the formula for population standard deviation ( ) stated?
a. The positive square root of the mean ÷ sum of squared differences between mean
and individual values
b. Square root of the mean ÷ (N 1)
c. The positive square root of the [(sum of squared differences between mean and
individual values) ÷ N]
d. The sum of squared differences ÷ the positive square root of the mean
ANS: C
Standard deviation describes the dispersion (or variance) of values around a central point
(typically the mean). Variance is calculated by summing the squared differences between the
population mean and each individual sample value and dividing this sum by the population
size. This results in a large number, thus SD is the positive square root of this variance.
DIF: 1
REF: Page 10
OBJ: 1 | 11
6. Two types of error may be encountered during analysis of a substance. The type of error that
occurs with a constant or predictable difference or trend, either positive or negative, and thus
is related to bias, is a(n) error.
a. systematic
b. random
c. analytical
d. All of the above are correct.
ANS: A
Systematic error is a component of error, which in the course of a number of analyses of the
same measure and/or analyte remains constant or varies in a predictable (proportional)
way. This type of error will directly influence the mean value and affects bias.
DIF: 2
REF: Page 7
OBJ: 1 | 7
7. A research project examining cholesterol values using a new Cholestcheck assay produces the
following cholesterol values from a random sample of 14, 25-year-old women:
Mean = 137 mg/dL
2 standard deviations = 6 mg/dL
6 | P a g eN = 14
The coefficient of variation percent for this assay is:
a. 1.14%.
b. 2.19%.
c. 4.38%.
d. 9.49%.
ANS: B
CV% is calculated by dividing a standard deviation by the mean and then multiplying that
value by 100%. In this case, one standard deviation is equal to 3 mg/dL (6 mg/dL ÷ 2), which
is divided by 137 and equals 0.02189. This value multiplied by 100% equals 2.189 or 2.19.
DIF: 2
REF: Page 20
OBJ: 11
8. You are performing a precision study on a new chemistry analyzer in your hospital lab by
analyzing a single sample many times. The study involves performing the analysis on
different shifts using different calibrators and analysis by different laboratorians. This aspect
of precision is referred to as:
a. repeatability.
b. reproducibility
c. validity.
d. reliability.
ANS: B
One aspect of precision is reproducibility, the closeness of agreement between results of
measurements performed under changed conditions of measurements (e.g., time, operators,
calibrators, and reagent lots).
DIF: 2
REF: Page 13
OBJ: 1 | 4
9. Following a precision study in which repeatability and reproducibility of 20 samples are
assessed, which one of the followingformulaewould be used to determine the total standard
deviation ( 2T)?
a.
2within-run/2 + 2between-run
b. (x2i x1i)
c.
(x1
)2/N
d. 2within-run + 2
between-run
ANS: D
The degree of precision is usually expressed on the basis of statistical measures of
imprecision, such as the standard deviation. The total standard deviation ( 2T) may be split
into within-run and between-run components using the principle of analysis of variance
components (variance is the squared standard deviation):
2T =
2within-run + 2between-run
DIF: 2
REF: Page 13
OBJ: 4 | 11
10. The ability of an analytical method to assess small variations of the concentration of an
analyte, and that is often expressed as the slope of the calibration curve, is referred to as:
a. analytical specificity.
b. analytical sensitivity.
c. limit of detection.
d. analytical range.
7 | P a g eANS: B
Analytical sensitivity is the ability of an analytical method to assess small variations of the
concentration of analyte. This is often expressed as the slope of the calibration curve.
DIF: 1
REF: Page 6
OBJ: 1 | 4
11. Method selection involves consideration of several different criteria. Assessment of a
candidate method’s precision, accuracy, and analytical specificity are components of which
one of the following categories?
a. Analytical performance criteria
b. Medical criteria
c. Instrument parameters
d. Descriptive measures criteria
ANS: A
In evaluation of the performance characteristics of a candidate method, precision, accuracy
(trueness), analytical range, detection limit, and analytical specificity are of prime importance.
These are aspects of analytical performance criteria.
DIF: 1
REF: Page 7-8
OBJ: 2
12. The statistical analysis used to compare values obtained by a new method with those obtained
by an established method is:
a. a Student t test.
b. standard deviation.
c. regression analysis.
d. limit of detection.
ANS: C
Regression analysis is commonly applied when comparing the results of analytical method
comparisons. Typically an experiment is carried out in which a series of paired values is
collected when comparing a new method with an established method.
DIF: 1
REF: Page 20
OBJ: 1 | 5
13. The Student t distribution:
a. compares a sample mean to a population mean using the population.
b. compares the means of two samples using sample statistics.
c. assesses the means of samples prior to and following some intervention.
d. assesses the significance of difference between more than two variables.
ANS: B
A Student t distribution analysis is commonly used in significance tests, such as the
comparison of sample means. Therefore, if a random sample can be taken from a Gaussian
population, then the sample SD can be calculated from the sample means.
DIF: 2
REF: Page 11
OBJ: 1 | 3
14. A list of intervals followed by a list of frequencies is referred to as a:
a. frequency histogram.
b. range.
c. cumulative frequency distribution.
d. frequency distribution.
ANS: D
8 | P a g eA frequency distribution is constructed by dividing the measurement scale into cells of equal
width; counting the number, ni, of values that fall within each cell; and either drawing a
histogram or listing the number of values in each cell.
DIF: 1
REF: Page 9
OBJ: 1
15. The type of regression analysis that is considered to reliably estimate the relationship between
modified target values and that takes into account errors in both methods 1 and 2 is
regression analysis.
a. Deming
b. ordinary least-squares
c. nonparametric
d. random error
ANS: A
To reliably estimate the relationship between modified target values, a regression procedure
taking into account errors in both x1 and x2 is preferable (a situation termed the Deming
approach). Although the OLR procedure is commonly used in method comparison studies, it
does not take errors in x1 into account but is based on the assumption that only the x2
measurements are subject to random errors.
DIF: 2
REF: Page 21
OBJ: 8
16. Comparisons of measurement values between clinical laboratories require a hierarchical
approach that obliges routine clinical chemistry measurements to be referred back to a
reference measurement procedure.Thisconcept isknown as:
a. uncertainty.
b. error.
c. traceability.
d. reliability.
ANS: C
To ensure reasonable agreement between measurements of routine methods, the concept of
traceability comes into focus. Traceability is based on an unbroken chain of comparisons of
measurements leading to a known reference value. A hierarchy of methods exists with a
reference measurement procedure at the top, selected measurement procedures at an
intermediate level, and finally routine measurement procedures at the bottom.
DIF: 2
REF: Page 28
OBJ: 1 | 9
17. To systematically assess errors associated with laboratory results, a parameter associated with
the result of a measurement that characterizes the dispersion of the values reasonably
attributed to the substance being measured is considered. This parameter is expressed by a
formula that includes preanalytical, analytical, and traceability components and is referred to
as:
a. uncertainty.
b. error.
c. traceability.
d. reliability.
ANS: A
To assess in a systematic way errors associated with laboratory results, the uncertainty
concept has been introduced into laboratory medicine. The formal definition of uncertainty is
“a parameter associated with the result of a measurement that characterizes the dispersion of
the values that could reasonably be attributed to the measurand.”
9 | P a g eDIF: 1
REF: Page 29
OBJ: 1 | 11
18. In a chemistry methods analysis, linearity refers to the:
a. closeness of agreement between independent results of measurements obtained
under stipulated conditions.
b. closeness of agreement between the average value obtained from a large series of
results of measurements and a true value.
c. analyte concentration range over which measurements are within the declared
tolerances for imprecision and bias of the method.
d. relationship between measured and expected values over the range of analytical
measurements.
ANS: D
Definition: linearity refers to the relationship between measured and expected values over the
range of analytical measurements.
DIF: 1
REF: Page 13
OBJ: 1 | 4
19. In the calibration hierarchy, a reference measurement procedure, which is a fully understood
procedure of highest analytical quality, is at the top. This procedure is associated with which
one of the following types of error?
a. Calibration error
b. Specificity error
c. Pure random error
d. Systematic error
ANS: C
A reference measurement procedure is associated only with pure, random error, whereas a
routine method typically has some additional bias related to errors in calibration and
limitations with regard to specificity.
DIF: 1
REF: Page 16
OBJ: 9
20. In a qualitative point-of-care test, clinical sensitivity is considered as the:
a. probability of classifying a result as positive.
b. probability of classifying a result as negative.
c. ability of an analytical method to assess small variations of the concentration of an
analyte.
d. ability of an assay procedure to determine specifically the concentration of the
target analyte in the presence of potentially interfering substances.
ANS: A
Qualitative point-of-care tests are primarily assessed on the basis of their ability to correctly
classify results in relation to the cutoff value. The probability of classifying a result as positive is
called the clinical sensitivity, while classifying a result as negative (below the cutoff) is termed
the clinical specificity.
DIF: 1
REF: Page 15
OBJ: 1
10 | P a g eChapter 03: Clinical Evaluation of Methods
MULTIPLE CHOICE
1. True negatives ÷ (false positives + true negatives) is the formula for determining:
a. sensitivity.
b. specificity.
c. the odds ratio.
d. the likelihood ratio.
2. The proportion of a population that has the particular disease being studied is referred to
as the:
a. prevalence.
b. predictive value.
c. positive value.
d. clinical sensitivity.
3. What is the positive predictive value of a test in which 220 tested individuals with positive
test results actually have the disease and 45 tested individuals with positive test results do
not have the disease?
a. 16.9%
b. 66%
c. 83%
d. 120%
Answers available here: http://bit.ly/3bYO4Zv
4. 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:
a. true positives.
b. false positives.
c. true negatives.
d. false negatives.
11 | P a g e5. 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: a. 111%. b. 100%. c. 90%. d. 75%.
6. A receiver operating characteristic (ROC) curve is a plot of: a. systematic error against random error. b. tumor marker decision levels versus upper limit of reference intervals. c. true positives versus false positives. d. specificity of one method against the specificity of another method.
Answers available here: http://bit.ly/3bYO4Zv
7. ROC curves are most useful in assessing the performance of quantitative laboratory analyses because: a. multiple tests for the same analyte can be evaluated at one time. b. they can display performance of tests over the entire range of decision values. c. they allow specific reference intervals to be determined for each analysis. d. they can evaluate combination testing in a single plot.
8. A laboratory analysis that produces quantitative results with an infinite number of sensitivity and specificity pairs is referred to as a
test.
a. predictive b. qualitative c. dichotomous d. continuous
9. Nondiseased individuals that are classified as diseased by having a positive result on a specific laboratory test are considered: a. true positives. b. false positives. c. true negatives. d. false negatives.
10. 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: a. false-positive results increase. b. true-negative results increase. c. the prevalence of the disease increases. d. the predictive value of a negative test increases.
Answers available here: http://bit.ly/3bYO4Zv
11. A method that can be used to calculate the probability of a disease after new information is added to previously obtained information involves: a. likelihood analysis. b. sensitivity analysis. c. Bayes theorem. d. combination testing.
12 | P a g e [Show Less]