TEST BANK FOR TIETZ FUNDAMENTALS OF CLINICAL CHEMISTRY AND MOLECULAR DIAGNOSTICS 7TH EDITION BY BURTIS

TEST BANK FOR TIETZ FUNDAMENTALS OF CLINICAL CHEMISTRY AND MOLECULAR DIAGNOSTICS 7TH EDITION BY BURTIS Table of Contents Chapter 01: Clinical Chemistry, Molecular Diagnostics, and Laboratory Medicine ................................. 2 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 ............................................................................................................... 38 Chapter 13: Mass Spectrometry ........................................................................................................... 41 Chapter 14: Enzyme and Rate Analyses .............................................................................................. 44 Chapter 15: Immunochemical Techniques ........................................................................................... 48 Chapter 16: Automation ....................................................................................................................... 51 Chapter 18: Amino Acids, Peptides, and Proteins .................................................................................. 54 Chapter 19: Serum Enzymes ............................................................................................................... 58 1 | P a g eChapter 01: Clinical Chemistry, Molecular Diagnostics, and Laboratory Medicine MULTIPLE 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 2 | P a g epowerful genetic testing. DIF: 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. 3 | P a g ed. screening for disease in the absence of clinical signs or symptoms. ANS: 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. 4 | P a g eANS: F The 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% 5 | P a g eANS: C The coefficient of variation is the measure of relative imprecision. The value of CV% is determined 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 6 | P a g e REF: Page 7 OBJ: 1 | 77. 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 N = 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 + 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 = DIF: 2 2within-run + 2between-run 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: 7 | P a g e 2between-runa. analytical specificity. b. analytical sensitivity. c. limit of detection. d. analytical range. ANS: 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: 8 | P a g ea. frequency histogram. b. range. c. cumulative frequency distribution. d. frequency distribution. ANS: D A 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. 9 | P a g ed. 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.” DIF: 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. 10 | P a g eDIF: 1 REF: Page 15 OBJ: 1 Chapter 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% 11 | P a g eAnswers available here: 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. 5. 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: 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. 12 | P a g eAnswers available here: 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. To calculate the sensitivity of a laboratory test to correctly classify true positives, one must first know the number of: a. true positives and false negatives. b. true negatives and false positives. c. true positives and false positives. d. false positives and false negatives. 13. To calculate the predictive value of a positive test, which of the following should be known? a. Sensitivity only b. Specificity and prevalence only c. Sensitivity and specificity only d. Sensitivity, specificity, and prevalence 14. 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: a. odds ratio. b. likelihood ratio. c. prevalence. d. predictive value. Answers available here: TRUE/FALSE 1. In regard to clinical evaluation of method, a high clinical sensitivity means few negatives. false Chapter 04: Evidence-Based Laboratory Medicine MULTIPLE CHOICE 1. Systematic reviews are used to assess and answer very specific clinical questions in an unbiased way. The most important of the steps in conducting a systematic review is the: a. formulation of the clinical question that will form the basis of the review. b. choosing of the reviewer who will perform the work. c. primary literature search and review. 13 | P a g ed. data extraction from the literature. 2. In reading a research article, you determine that the study design was flawed because there was no control group. This is an example of a weakness in: a. internal reliability. b. internal validity. c. external reliability. d. external validity. Answers available at 3. When developing clinical practice guidelines, what is the critical first step? a. Requesting input from health insurance companies and government officials b. Preparing a cost analysis based on patient needs c. Determining the intended group that will be directly involved with implementation d. Selecting and refining the topic upon which the investigation will center 4. Another way that “bias” can be defined is as a. random b. systematic c. analytical d. clinical Answers available at 5. Internal validity is the: a. degree to which the variables in the study apply to all individuals in the study. b. degree to which the results of your sample can be inferred to the general population outside of your study. c. equivalent of consistency. d. calculation of mean and variance from repeated measures. 6. During diagnostic accuracy studies in evidence-based laboratory medicine, a laboratory test being studied, for example, produces results that are compared with the gold standard of testing, which would be the currently used assay or assay system. The test of interest is referred to as a(n): a. index test. b. reference standard. c. outcome study. d. practice test. Answers available at 7. A research study was prepared to assess the diagnostic accuracy of a therapeutic drug monitoring assay for HMG-CoA reductase inhibitors (statins). The study was flawed with poor design. Which of the following statements are correct? a. Random error decreased. b. Systematic error decreased. c. Systematic error increased. d. Both a and b are correct. 8. In a randomized control trial, the use of a new vaccine was observed to reduce the number Chlamydia trachomatis infections in a population of college-aged women. This finding is referred to as a(n): a. clinical audit. 14 | P a g e _ error.b. systematic review. c. patient outcome. d. internal validator. 9. If the evidence overwhelmingly points toward the introduction of a new laboratory analysis and practice, yet physicians fail to incorporate the new test into their clinical practice, what component of evidence-based laboratory medicine will reveal this? a. Clinical audit b. Economic evaluation c. Systematic review d. Clinical practice guidelines 10. In a research study, a physician asks if the results from the therapeutic drug assay will be able to predict the patient’s eventual health outcome. A study to determine this is referred to as a: a. patient outcome study. b. case-control study. c. systematic review. d. prognostic value study. Answers available at 11. Following a systematic review, random control studies, clinical audit, and a cost evaluation, an assay for assessment of growth hormone level as a predictor of bone cancer has been recommended by a group of orthopedic surgeons to be performed in your chemistry laboratory. What is the next step before implementation of the assay? a. Evaluating the costs of alternative methods to produce similar outcomes b. Developing a clinical practice guideline for implementation of the assay c. Performing a meta-analysis d. Beginning a second round of randomized control trials 12. Following a systematic review, random control studies, clinical audit, and a cost evaluation, an assay for assessment of growth hormone level as a predictor of bone cancer has been recommended to be performed in your chemistry laboratory. What might be an issue if the group recommending this assay was composed of all oncologists? a. This group would likely not have the expertise needed to suggest implementation and develop a guideline. b. This specialty group of physicians might be motivated to implement this test to produce income for the group practice. c. The systematic review, research studies, and statistical analysis would be beyond the scope of this group of physicians. d. There is nothing inappropriate about this group because they are experts in the field. 13. STARD: a. relates to the four components of economic evaluation in an evidence- based laboratory medicine study. b. is the assessment of the value of a test analysis for those individuals who are tested. c. is a set of guidelines assembled to put into practice the findings of an evidence-based laboratory medicine study. d. includes a listing of items that need to be included in reports of studies on diagnostic accuracy. 15 | P a g e14. QALY: a. is associated with a quality systematic review of literature. b. assesses the quality of a diagnostic accuracy study. c. is an outcome achieved in cost-utility analysis. d. relates to the implementation of the findings of a clinical audit. Answers available at 15. In a study of diagnostic accuracy, the selection of the study groups was not random and included only a few individuals in each group. This would likely affect which one of the following? a. Internal validity b. External validity c. The clinical reference standard d. Index test Chapter 05: Establishment and Use of Reference Values MULTIPLE CHOICE 1. Even if somewhat impractical, which one of the following preanalytical factors should be standardized when establishing a reference interval for an analyte? a. Location (building, city, etc.) in which the venipuncture is performed b. The method of specimen collection c. Reagents used in analyte analysis d. The specific method used for analysis Answers available 2. To determine the confidence intervals of percentiles of ranked data (data arranged by magnitude of value), it is most appropriately assessed using: a. nonparametric testing. b. univariate analysis. c. parametric testing. d. multivariate analysis. 3. True negatives ÷ (false positives + true negatives) 100 is the formula for determining: a. clinical sensitivity. b. clinical specificity. c. analytical sensitivity. d. analytical specificity. 4. 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 this test is: a. 111%. b. 100%. c. 90%. d. 75%. 16 | P a g eAnswers available 5. Which one of the following is an example of an exclusion criterion when establishing a healthy population-based reference interval? a. Use of oral contraceptives b. Sex c. Age d. Ethnicity 6. An important assumption that is made when using parametric methods to estimate percentiles and their confidence intervals in determining reference limits is that: a. the type of distribution that the reference values exhibit is a t-distribution. b. the true distribution that the reference values exhibit is Gaussian. c. the distribution parameters cannot be estimated. d. there is no set distribution pattern of reference values. Answers available 7. A physician asks your laboratory to begin 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 those 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 this claim? a. Subject-based reference values more closely resemble the group of reference individuals that were used to establish population-based reference intervals. b. Standardized laboratory methods produce more accurate results when examining individual subject values. c. Subject-based reference values are more easily tracked and applied in settings in which large numbers of specimens are analyzed. d. Changes in a subject-based reference value might indicate altered biochemical status yet still be within the population-based healthy reference interval. 8. What is the statistical range of the following distribution of data? 21 23 26 a. 18 to 26 b. 21.6 c. 8 d. 8 9. The proportion of a population (or of those being tested) with the disease being studied is referred to as the: a. prevalence. b. clinical sensitivity. c. clinical specificity. d. predictive value. 10. To reduce workload in your chemistry laboratory, you are setting up a small laboratory on the opposite side of your large city from the main laboratory. When preparing the new laboratory’s chemistry analyzer, you decide to use the reference values that have been generated by the main laboratory’s chemistry analyzer, which is a larger model (but similar in 17 | P a g eall other respects) than yours. Can this be justified? a. No, because each analyzer will produce completely different results from the other laboratory. b. No, because the populations that will be tested are completely different. c. Yes, if certain conditions have been fulfilled, such as population matching, data comparison, analytical performance agreement, and specimen standardization. d. Yes, because you cannot afford to perform reference value determinations in your laboratory. 11. Visually inspecting the distribution of reference values can provide a safeguard against misinterpretation of statistical methods, and it may provide valuable information about the data. Which of the following observations might represent erroneous values? a. Skewed distributions b. Outlier values c. Partition criteria d. Bimodal distributions Answers available 12. The results of a certain type of quantity obtained from a single individual or group of individuals corresponding to a stated description is the definition of: a. reference intervals. b. reference limits. c. clinical decision limits. d. reference values. Chapter 06: Specimen Collection, Processing, and Other Preanalytical Variables MULTIPLE CHOICE 1. When a coagulated blood sample is separated by centrifugation, the liquid component is separated from the cells. This “serum” is the: a. liquid component with all clotting factors present in it. b. liquid component with no clotting factors in it. c. unclotted cellular component. d. clot. 2. An example of an uncontrollable preanalytical variable would be: a. improper specimen collection. b. preanalytical errors. c. prolonged bed rest. d. an individual’s age. 3. The best use of a saliva specimen would be for which one of the following analyses? a. Measurement of blood group substances to determine secretor status and genotype 18 | P a g eb. Determination of whether the specimen is an effusion or an exudate c. Early gestational age diagnosis of inherited genetic disorders d. Characterization of the type of arthritis present in an individual Answers available at 4. Hemolysis will cause potassium when analyzed. a. and lactate dehydrogenase (LD) values to appear increased b. value to appear increased and LD value to appear decreased c. value to appear decreased and LD value to appear increased d. and LD values to appear decreased 5. The type of urine specimen that is best for detection of abnormal amounts of certain analytes such as chorionic gonadotropin for pregnancy testing is a: a. random and untimed specimen. b. 24-hour collection. c. clean, early morning, fasting specimen. d. catheter specimen. 6. Arthrocentesis is a technique used to collect: a. pleural fluid. b. blood. c. synovial fluid. d. amniotic fluid. 7. An amniotic fluid specimen for bilirubin analysis is received in the laboratory in a clear plastic collection tube. How will this affect the results of the bilirubin analysis? a. There will be no effect on the bilirubin analysis results, because this specimen is properly collected. b. Because the tube is not darkened, light will cause the bilirubin to be photo-degraded and the results will be falsely decreased. c. Because there is no additive in the tube, the amniotic fluid cells will hemolyze, leading to a false increase in bilirubin. d. Because the tube is made of plastic, the amniotic fluid will clot, and no analysis can be performed on a clotted sample. Answers available at 8. As an anticoagulant, heparin acts to: a. chelate calcium. b. inhibit platelet aggregation. c. antagonize vitamin K. d. activate antithrombin. 9. Which one of the following anticoagulants is considered unacceptable for a blood sample that will be used for DNA amplification in the polymerase chain reaction? a. Heparin b. EDTA c. Iodoacetate d. Acid citrate dextrose 10. An individual has several laboratory tests ordered and is having blood collected. After applying the tourniquet, the phlebotomist has to answer the phone and write down a message, leaving the tourniquet in place for approximately 3 minutes. How will this affect this individual’s serum composition of total protein and potassium? 19 | P a g ea. Both will be increased. b. Total protein will be increased and potassium will be decreased. c. Total protein will be decreased and potassium will be increased. d. Both will be decreased. Answers available at 11. An individual has several laboratory tests ordered and is having blood collected. After applying the tourniquet, the phlebotomist has to answer the phone and write down a message, leaving the tourniquet in place for approximately 3 minutes. How will this affect this individual’s serum composition of bilirubin? a. It will be increased. b. It will be decreased c. It will not be affected. 12. Which one of the following analytes shows no difference in composition between a serum and a plasma specimen? a. Lactate dehydrogenase b. Potassium c. Cholesterol d. Total protein 13. A blood collection tube containing a specific amount of additive is only half filled with blood instead of being completely filled. Will this collection affect laboratory test results? a. There will be no effect on the results because the additive is “calibrated” for any amount of blood in the tube. b. There will be a significant effect on the test results because the additive must be mixed with a full tube of blood to achieve its appropriate effect. Answers available at 14. When collecting a timed urine specimen for laboratory analysis: a. all of the urine must be collected at once into one large container instead of using smaller separate containers that are emptied into the large container. b. the container used for collection must be maintained at room temperature throughout the entire collection period. c. it is acceptable and best practice to collect the urine into one container containing two different mixed preservatives if more than one test is ordered. d. the individual’s bladder must be emptied first at the beginning of the time of collection, and this urine is discarded. 15. A skin puncture of an individual’s finger is ordered for hematocrit analysis and is to be collected into a capillary tube. It is cold in the phlebotomy area, and the phlebotomist notices that the individual appears cold and pale. What should the phlebotomist do to stimulate blood circulation to the finger so an acceptable fingerstick specimen will be obtained? a. Slap the individual’s hand to warm it up. b. Tie a tourniquet around the individual’s finger. c. Warm the finger for 3 minutes using a warming device. d. Massage the finger and hand. 16. An example of a preanalytical error would be: a. mislabeling a tube of blood with an incorrect name. b. using expired reagents in an analysis. 20 | P a g ec. sending the test results to the incorrect physician. d. failing to run controls with unknown samples. 17. The best additive in a collection tube for enhancing the vitality and recovery of white blood cells for isolation of genomic DNA is: a. sodium citrate. b. heparin. c. oxalate. d. acid citrate dextrose. Answers available at MATCHING Using each answer only once, match the color of the evacuated blood collection tube stopper with the additive in that tube. a. Yellow b. Lavender c. Gray d. Green Chapter 07: Quality Management MULTIPLE CHOICE 1. If alerted to a control problem when using Westgard multirules, an analyst should first: a. assess the analytical method, equipment, reagents, and specimens. b. rerun controls several times until the values finally are acceptable. c. call the laboratory manager. d. call the manufacturer’s repair hotline. 2. Upon examination of the week’s analytical run of plasma glucose tests, you notice that four consecutive normal control values are +1 s (standard deviation) from the mean. In your QC report, you note that Westgard multirule has been broken and realize that this rejection rule is sensitive to a. 14s; random b. 41s; systematic c. R4s; systematic d. 4Rs; random Answers available at 3. Upon examination of the week’s analytical run of plasma glucose tests, you notice that four consecutive normal control values are +1 s (standard deviation) from the mean. In your QC report, you note that a Westgard multirule has been broken and realize that this rejection rule is sensitive to a specific type of error. An example of this type of error would be: a. poor pipetting technique. b. incubator temperature change. c. improper calibrator preparation. d. unstable photometer. 21 | P a g e error.4. Preparation of a CLSI-defined procedure document of an analytical protocol is a means of controlling which one of the following types of variables? a. Analytical b. Preanalytical c. Postanalytical d. Reproducibility 5. Which one of the following would be considered a postanalytical variable in regard to laboratory services? a. Test ordering b. Specimen acquisition c. Test procedures d. Result reporting A ns w er s a va ila b le at h ttp :/ /b it. ly /2 w F x s W u 6. The Westgard multirules for quality control were designed to interpret control data and to aid in troubleshooting. The rule stated as 22s is interpreted as meaning: a. one control value has exceeded ±2 s from the mean. b. two consecutive control values have exceeded the mean ±2 s. c. two consecutive control values have exceeded the mean ±1 s. d. four consecutive controls have exceeded the mean ±2 s. Answers available at 7. Lean Production: a. involves use of simulated patient specimens made from a common pool to determine the “quality” of a laboratory’s performance using standard deviation calculations. b. is a quality performance goal that requires a specific number of standard deviations of process variation to fit within the tolerance limits for the process. c. is a quality process that focuses on creating more value by eliminating activities that are considered wasteful. d. is a set of international standards for quality management produced by the International Organization for Standardization. 8. Which one of the following would be considered a cost of nonconformance? a. Performing preventive maintenance on analyzers b. Employee training c. Repeating an analytical run because the QC is out of range d. Sending an employee to a fire safety class 9. Six Sigma processes: a. use simulated patient specimens made from a common pool to determine the “quality” of a laboratory’s performance using standard deviation calculations. b. are quality performance goals that require a specific number of standard deviations of process variation to fit within the tolerance limits for the process. c. are focused on creating more value by eliminating activities that are considered waste. d. are international standards for quality management produced by the International Organization for Standardization. 22 | P a g eAnswers available at 10. Upon examination of the control chart of the week’s analytical run of serum creatinine, you notice that 10 consecutive level II control values lie on the same side of the mean. In your QC report, you note that Westgard multirule has been broken and realize that this rejection rule is sensitive to a. 10 ; random b. 10 ; systematic c. X10; random d. X10; systematic 11. Upon examining a Levey-Jennings control chart for analyte X, you notice that on day 6 the one control was 2.5 s from the mean and the duplicate control was +3.3 s from the mean. Which of the following Westgard control rules was/were broken? a. 41s and 22s b. R4s and 13s c. R4s and 22s d. 22s only 12. Which one of the following statements concerning the use of internal control materials is incorrect? a. Use of control materials can aid in the identification of assay malfunctions that lead to unreliable data. b. Serum controls are prepared from human serum pools and are analyzed in analytical runs that are separate from patient samples. c. QC data are collected over a period of time and statistically analyzed using measures of central tendency. d. Controls that exceed specific limits are examined with the Westgard rules to determine what kind of error is present and what actions are to be taken. 13. In regard to a Gaussian distribution, ±2 s from the mean encompasses a. 99.7% b. 98.0% c. 95.5% d. 68.2% 14. Random error would be caused by: a. contaminated reagents. b. pipetting errors. c. inappropriate preparation of calibrators. d. low volume reagent blanks. 15. According to CLIA regulations, a score of must be attained on three consecutive external proficiency test challenges for a laboratory to be accredited and continue patient testing. a. 50% b. 60% c. 70% d. 80% 16. You have received your proficiency test results from the accrediting agency and note that your creatinine result was unacceptable at greater than 2 SDI from the group mean. The value that was entered on your survey report form was 15 mg/dL. The group method mean 23 | P a g e of values. 1.3 mg/dL, with a method standard deviation of 0.3 mg/dL. You realize that your laboratory made an error in entering the result. If you had entered 2.0 mg/dL as the result on your survey report, what would the correct SDI be? a. 45.6 SDI Answers available at b. 4.56 SDI c. 1.08 SDI d. 0.67 SDI 17. You have received your proficiency test results from the accrediting agency and note that your creatinine result was unacceptable at greater than 2 SDI from the group mean. The value that was entered on your survey report form was 15 mg/dL. The group method mean was 1.3 mg/dL with a method standard deviation of 0.3 mg/dL. You realize that your laboratory made an error in entering the result. If you had entered 2.0 mg/dL as the result on your survey report, would the recalculated SDI now be in agreement with the rest of the laboratories in the testing program? a. Yes b. No c. Cannot determine from information given 18. Two types of error may be encountered during chemical analysis of a substance. The type of error that occurs as a result of contaminated calibrating solutions would be error. a. systematic b. random c. analytical d. calibration 19. You arrive at the clinical chemistry laboratory one morning and discover that personnel from the third shift left you the QC sheet from the thyroid-stimulating hormone (TSH) run. The technician has circled the level I TSH control values, and you realize that all six of the level I control values are +3 s from the mean. No results have been released. Now it’s your decision regarding what to do next. First, which Westgard rule(s) has (have) been violated? a. 22s b. 41s c. 13s d. All of the above rules have been broken. 20. You arrive at the clinical chemistry laboratory one morning and discover that personnel from the third shift left you the QC sheet from the thyroid-stimulating hormone (TSH) run. The technician has circled the level I TSH control values, and you realize that all six of the level I control values are +3 s from the mean. No results have been released. Now it’s your decision regarding what to do next. What is your decision regarding the release of results in the problem stated in the preceding question? a. Hold all results, reject the run, and troubleshoot. b. Release results and do nothing else. c. Release all results and troubleshoot. d. Call the manufacturer’s representative and ask him what to do. 21. You arrive at the clinical chemistry laboratory one morning and discover that personnel from the third shift left you the QC sheet from the thyroid-stimulating hormone (TSH) run. The technician has circled the level I TSH control values, and you realize that all six of the level I control values are +3 s from the mean. No results have been released. Now it’s your decision regarding what to do next. What kind of error is most likely occurring? a. Random error due to pipetting errors 24 | P a g eb. Systematic error due to calibration issues 22. According to the five-Q framework, the “QP” refers to quality: a. programming. b. planning. c. processes. d. precision. Answers available at 23. What is the role of quality planning in the five-Q framework of quality? a. To monitor the laboratory as a whole for result quality b. To monitor the statistical analysis of results c. To ensure that the laboratory's performance satisfies quality requirements d. To identify the cause of a problem and find a remedy for that problem 24. The first step in the development of an in-service training program using an instructional system for employee competency in the laboratory is: a. direct observation of routine patient test performance. b. preparation of a written procedure. c. implementation of a schedule. d. a needs assessment or gap analysis. Chapter 08: Principles of Basic Techniques and Laboratory Safety MULTIPLE CHOICE 1. To make 20 mL of a 0.1 g/L solution from a 10 mg/mL stock solution, you should add mL of the stock solution to mL of solvent. a. 2; 18 b. 10; 10 c. 1; 19 d. 0.2; 19.8 2. Which one of the following statements concerning type I water is not correct? a. Type I water is acceptable for analytical purposes. b. Testing that requires minimal interferences (such as iron or enzyme analysis) requires the use of type I water. c. Type I water is obtained from distillation only and contains a few impurities. d. Type I water results in part from ion exchange purification and reverse osmosis. 3. What is the relative centrifugal force (RCF) for a centrifuge spinning at 1200 rpm with a rotor head radius of 8 inches? a. 32.7 g b. 3200 g c. 130 g d. 1300 g 25 | P a g eAnswers available at 4. Reverse osmosis is: a. the process of vaporizing and condensing a liquid to purify or concentrate a substance or to separate a volatile substance from less volatile substances. b. a process by which water is forced through a semipermeable membrane that acts as a molecular filter. c. a process that removes ions to produce mineral-free deionized water. d. a process used to convert a liquid or a volatile solid into vapor. 5. The National Institute for Occupational Safety and Health of the CDC distributes a document that specifies how U.S. clinical laboratories should handle infectious agents. This document is referred to as: a. the Chemical Hygiene Plan. b. the Exposure Control Plan. c. HAZMAT. d. Universal Precautions. 6. A highly purified chemical that is directly weighed or measured to produce a solution whose concentration is exactly known is referred to as a: a. calibrator. b. primary reference material. c. secondary standard. d. working solution. 7. Chemicals with the designation are suitable for use in most clinical chemistry laboratory analyses. a. technical grade b. analytical reagent grade c. USP (United States Pharmacopeia) d. NF (National Formulary) 8. What is the molarity (mol/L) of a solution containing 25 g of H2SO4 (MW= 98 g) in 150 mL of deionized water? a. 1.7 mol/L b. 0.59 mol/L c. 0.002 mol/L d. 16.3 mol/L 9. How many grams of NaCl (MW = 58.5 g) are required to prepare 250 mL of a 6 mol/L solution of NaCl? a. 87.75 g b. 58.5 g c. 585 g d. 877.5 g Answers available at 10. What is the normality of a solution containing 20 g of H2SO4 (MW = 98) in 500 mL of buffer? a. 8.2 N b. 2.8 N 26 | P a g ec. 0.82 N d. 176.8 N 11. Universal Precautions: a. consist of shipping standards that divide potentially infectious specimens or substances into risk groups. b. state that only HIV, hepatitis, and sexually transmitted disease-positive specimens should be considered and handled as infectious material. c. state that hand washing is only necessary before entering a clinical laboratory. d. consist of guidelines that in part necessitate the wearing of barrier protection when handling potentially infectious material. 12. You have seen another laboratorian collecting blood from a patient without using any barrier protection. What safety mandate is this employee ignoring? a. Chemical hygiene plan b. Universal Precautions c. Clinical laboratory plan d. Tuberculosis exposure plan 13. The one technical aspect of a clinical laboratory that has received considerable attention in the need for ergonomic design to decrease musculoskeletal stress would be: a. pipetting. b. chair design. c. lighting. d. flooring. Answers available at 14. Regarding centrifugation, what is the formula for calculating relative centrifugal force (RCF)? a. RCF = 1.118 r (in cm) rpm2 b. RCF = 1.118 10 5 c. RCF = 1.118 10 5 r (in cm) r2 (in cm) d. RCF = 1.118 r (in inches) rpm2 15. Fifty milligrams (mg) per 1000 mL is equal to: a. 0.005 g/mL. b. 0.050 g/mL. c. 0.050 g/L. d. 0.50 mg/mL. 16. What is the Clinical and Laboratory Standards Institute (CLSI) recommendation for the most appropriate RCF and time for centrifugation of blood samples to obtain sufficient separation of cellular and liquid components? a. 2000 g for 20 min b. 1200 g for 10 min c. 500 g for 10 min d. 100 g for 15 min 17. The class of fire that involves flammable liquids and gases is class and the recommended extinguisher agent is: a. A; water. b. B; water. 27 | P a g e rpm2 rpmc. B; dry chemical or carbon dioxide. d. C; Halon 1211 foam. 18. The type of pipette that is a piece of glass tubing drawn out to a tip and graduated uniformly along its length and is used for reagent measurement is referred to as a: a. transfer pipette. b. volumetric pipette. c. micropipette. d. measuring pipette. Answers available at 19. The increased use of electronic health record (EHR) systems has amplified the need for standardized communication between EHR and other systems. The newest universal code system that has standardized terms for all kinds of laboratory observations and measurements and includes a code number, a long formal name, a shorter name, and synonyms is referred to as the: a. Occupational Safety and Health Act. b. Clinical and Laboratory Standards Institute system. c. Logical Observation Identifier Names and Codes system. d. National Fire Protection Association system. TRUE/FALSE 1. The maximum amount of working volume of a flammable solvent allowed outside a storage cabinet is 1 gallon per room. Chapter 09: Optical Techniques MULTIPLE CHOICE 1. In regard to absorption photometry, absorbance is calculated from transmittance by which one of the following formulae? a. A = log %T 2 b. A = log T c. A = log T d. A = abc 2. Which one of the following statements best describes Beer law? a. The concentration of a substance is inversely proportional to the logarithm of transmitted light. b. Absorbance is inversely proportional to the logarithm of the concentration. c. Transmitted light is directly proportional to the concentration of a substance in solution. d. Intensity of incident light divided by intensity of transmitted light equals concentration. 3. There are several interferences that can affect or limit fluorescence measurements. For example, the inner filter effect: a. occurs when the solution absorbs greater than 2% of the exciting light, producing a nonlinear response between concentration and fluorescence emission. b. involves fluorophores that have overlapping excitation and emission spectra 28 | P a g eand that are susceptible to loss of detection because of background light scatter. c. involves solvents such as ethanol that cause appreciable fluorescence due to the interaction of the fluorophore with the solvent. d. is caused by light scattering of proteins and other macromolecules in the sample matrix, which might cause unwanted background fluorescence. Answers available at 4. A molecule is said to fluoresce when it absorbs light at one wavelength and emits light of: a. a lower energy. b. a shorter wavelength. c. a higher energy. d. the same wavelength. 5. In regard to atomic absorption (AA) spectrophotometry, which one of the following statements is correct? a. The technique combines laser-induced fluorometry and particle light scattering analysis to differentiate molecules, cells, or particles by size and shape. b. The technique measures concentration through the detection of absorbance of electromagnetic radiation by atoms of elements instead of molecules. c. Oxidation of an organic compound such as luminol induces an excited state, and light is emitted when the electron returns to the ground state. d. The amount of light scattered at right angles to the incident light is directly proportional to the concentration of the analyte of interest. 6. Which one of the following statements concerning nephelometry is correct? a. Nephelometry is the measure of the concentration of particles by measuring the amount of incident light blocked by the particles. b. In a nephelometric measurement, light blocked by solutes in the solution at 180° from the incident light is measured by a photodetector. c. The decrease in the intensity of scattered light is directly proportional to the number of particles in the solution, and the measurement of this decrease is called nephelometry. d. In a nephelometric procedure, the measurement of scattered light that is not in the direct path of the transmitted light is made at right angles to the incident light. 7. A blood specimen is obtained from an individual who is known to have elevated lipids and the serum appears milky. This individual’s physician has ordered an estrogen immunoassay that your laboratory performs using a nephelometric technique. Which one of the following statements is correct concerning the possible outcome of this assay? a. Certain components of this individual's sample will likely produce excess fluorescence by the phenomenon called “solvent effect” in the nephelometric assay. b. The lipemic specimen will produce interfering background light intensity and excess light scatter in this type of assay. c. The sample flow rate will be affected through the analyzer’s nebulizer because of the altered density of the sample. d. Elevated serum lipids will not interfere with this assay because nephelometry is not affected by any type of sample variability. 8. A monochromator’s filter must be tested to determine whether it can isolate a specific part of 29 | P a g ethe electromagnetic spectrum. Percent transmittance (%T) of light is plotted against a specific wavelength in nanometers. It is noted at which wavelengths 50%T (one half of the peak transmittance) occurred. This type of test assesses the filter’s: a. linearity. b. spectral bandwidth. c. calibration. d. absorbance spectrum. 9. A manual stat protein analysis is performed on a patient sample. The patient’s unknown sample had an absorbance reading of 0.6. The protein calibrator with an absorbance reading closest to the unknown's absorbance had a concentration of 6 g/dL and an absorbance reading of 0.5. Applying Beer law, calculate the unknown protein concentration in the patient sample. a. 6 g/dL b. 7.2 g/dL c. 8 g/dL d. 5.5 g/dL Answers available at 10. Which one of the following would be a limitation in a nephelometric measurement that might produce faulty values? a. Excess antigen in the antigen/antibody reaction b. Too much fluorophore in the analyte/fluorescing compound mixture c. Incorrect filter used to isolate a specific wavelength d. Absorption by a closely related atomic species 11. In spectrophotometric determinations, which of the following is the formula for calculating the absorbance of a solution? a. (Molar absorptivity length of light path)/concentration in mol/L b. (Molar absorptivity concentration in g/dL)/length of light path c. Molar absorptivity length of light path concentration in mol/L d. (Length of light path concentration in g/dL)/molar absorptivity 12. A standard calibrator solution of glucose has a concentration of 125 mg/dL and gives an absorbance of 0.20. Assuming a linear reaction, what is the co