Exam 2 MLS 407
In which zone might an antibody-screening test be false negative? a. Prozone b. Zone of Equivalence c. Postzone d. None of the above
a. Prozone
Which autoantibodies are strongly associated with granulomatosis with polyangiitis (Wegener's granulomatosis)? a. ANA b. ANCA c. AMA d. SMA
b. ANCA
Which of the following is associated with an increase in IgE production? a. Transfusion reaction b. Activation of Th2 cells c. Reaction to poison ivy d. Hemolytic disease of the fetus and newborn
b. Activation of Th2 cells
To determine if a patient is allergic to ryegrass, the best test to perform is the: a. total IgE test b. skin prick test c. DAT d. complement fixation
b. skin prick test
Which of the following best describes competitive binding assays? a. A limited number of binding sites are present b. The concentration of patient antigen is directly proportional to the label detected c. All patient antigen present is allowed to bind d. Labeled and unlabeled analyte are present in equal amounts
a. A limited number of binding sites are present
Which of the following refers to the force of attraction between and antibody and a single antigenic determinant? a. Affinity b. Avidity c. Van der Waals attraction d. Covalence
a. Affinity
Which of the following would support a diagnosis of drug-induced lupus? a. Anti-histone antibodies b. Antibodies to Smith antigen c. Presence of RF d. Antibodies to SS-A and SS-B antigens
a. Anti-histone antibodies
A 20-year-old woman made an appointment to see her physician because she was experiencing intermittent diarrhea. Laboratory testing revealed that she also had an iron-deficiency anemia. To determine if the patient has celiac disease, her doctor should order which of the following laboratory tests? a. Anti-tTG b. Anti-gliadin c. Anti-gluten d. All of the above
a. Anti-tTG
Which of the following is associated with anaphylaxis? a. Buildup of IgE on mast cells b. Activation of complement c. Increase in cytotoxic T cells d. Large amount of circulating IgG
a. Buildup of IgE on mast cells
Which of the following is an advantage of enzyme immunoassay over radioimmunoassay? a. Decrease in hazardous waste b. Shorter shelf life of kit reagents c. No interference by biological inhibitors d. Must be read immediately
a. Decrease in hazardous waste
Agglutination of dyed bacterial cells represents which type of reaction? a. Direct agglutination b. Passive agglutination c. Reverse passive agglutination d. Agglutination inhibition
a. Direct agglutination
Typing of RBCs with reagent antiserum represents which type of reaction? a. Direct hemagglutination b. Passive hemagglutination c. Hemagglutination inhibition d. Reverse passive hemagglutination
a. Direct hemagglutination
Which of the following can uniquely cause interferences in immunoassays designed with streptavidin bound to the solid-phase surface? a. Elevated concentration of biotin in the patient test sample can cause falsely increased results. b. Heterophile antibodies present in the patient sample cause falsely decreased results c. Antibody excess in the patient sample leads to a hook effect d. Solid-phase particles will dissolve easily if the reaction temperature is increased
a. Elevated concentration of biotin in the patient test sample can cause falsely increased results.
How do heterogeneous immunoassays differ from homogeneous immunoassays? a. Heterogeneous immunoassays require a separation step b. Heterogeneous immunoassays require less technical skill to perform than homogeneous immunoassays c. For noncompetitive immunoassays, the concentration of patient analyte is indirectly proportional to bound label in heterogeneous immunoassays d. Homogeneous immunoassays have better analytical sensitivity compared with heterogeneous immunoassays
a. Heterogeneous immunoassays require a separation step
The fluorescent antinuclear antibody test for lupus is an example of which of the following? a. Indirect fluorescence testing b. Direct fluorescence testing c. Competitive immunoassay d. Immunofixation
a. Indirect fluorescence testing
Destruction of the myelin sheath of axons caused by the presence of antibody is characteristic of which disease? a. Multiple sclerosis b. Myasthenia gravis c. Graves' disease d. Anti-glomerular basement membrane disease
a. Multiple sclerosis
To what does in situ hybridization refer? a. Probes react with intact cells within tissues b. Probes are protected from degradation if hybridized c. RNA polymerase copies messenger RNA d. Hybridization takes place in solution
a. Probes react with intact cells within tissues
Which is associated only with RNA synthesis? a. Promoter b. Cytosine c. S phase d. Primer
a. Promoter
Which technique represents a single-diffusion reaction? a. Radial immunodiffusion b. Ouchterlony diffusion c. Counter immunoelectrophoresis d. Immunofixation electrophoresis
a. Radial immunodiffusion
Which assay poses the greatest risk of exposure to biohazards? a. Radioimmunoassay b. Enzyme immunoassay c. Chemiluminescent immunoassays d. Fluorescence polarization
a. Radioimmunoassay
Anti-CCP (cyclic citrullinated peptide) is specifically associated with which autoimmune disease a. Rheumatoid arthritis b. Myasthenia gravis c. Autoimmune hepatitis d. Systemic sclerosis
a. Rheumatoid arthritis
Identify the characteristic associated with noncompetitive enzyme immunoassays. a. They are less sensitive than agglutination reactions b. They are used when quantitation is necessary c. Binding sites for patient antibody are limited d. Antibody is bound to the solid phase
a. They are less sensitive than agglutination reactions
Which of the following explains the difference between type II and type III hypersensitivity reactions? a. Type II involves cellular antigens b. Type III involves IgE c. IgG is involved only in type III reactions d. Type II reactions involve no antibody
a. Type II involves cellular antigens
The assembly of particles into visible clumps is called: a. agglutination b. equivalence c. precipitation d. sensitization
a. agglutination
All of the following may contribute to autoimmunity except: a. clonal deletion of self-reactive T cells b. molecular mimicry c. increased expression of class II MHC molecules d. polyclonal activation of B cells
a. clonal deletion of self-reactive T cells
The characteristic antinuclear antibody pattern produced by antibody to DNA-histone complexes is: a. homogeneous b. speckled c. peripheral d. nucleolar
a. homogeneous
The end-point radial immunodiffusion assay: a. is read after antigen-antibody equivalence is reached b. is the most rapid immunodiffusion method c. can be converted to a kinetic method by application of electrical current d. requires only a negative control for interpretation
a. is read after antigen-antibody equivalence is reached
A fluorescent substance is best described as one in which: a. light energy is absorbed and converted to a longer wavelength b. the emitted wavelength can be seen under normal white light c. there is a long time between the absorption and emission of light d. it spontaneously decays and emits light
a. light energy is absorbed and converted to a longer wavelength
The measurement of light scattered at an angle by the antigen-antibody complexes in a solution is called: a. nephelometry b. agglutination c. turbidimetry d. equivalency
a. nephelometry
If the concentration of free antibody (Ab)= 3 mol/L, the concentration of free antigen (Ag) = 2 mol/L, and the concentration of antigen-antibody complex = 6 mol/L, then the equilibrium constant K equals: a. 4 b. 1 c. 9 d. 2
b. 1
Which probe sequence will hybridize to 5'AGTCGATCGATGC3'? a. 5'TCAGCTAGCTACG3' b. 5'GCATCGATCGACT3' c. 5'AGTCGATCGATGC3' d. 5'CGTAGCTAGCTGA3'
b. 5'GCATCGATCGACT3'
Which of the following would be considered a significant finding in Graves' disease? a. Increased TSH levels b. Antibody to TSH receptor c. Decreased T3 and T4 d. Anti-thyroglobulin antibody
b. Antibody to TSH receptor
Which of the following is characteristic of a passive agglutination test? a. The antigen-antibody reaction is competitive (no agglutination indicates a positive result). b. Antigen molecules are artificially bound to particles c. Antibody is attached to particles d. The antigen is naturally found on particles
b. Antigen molecules are artificially bound to particles
What immune phenomenon is responsible for the muscle weakness associated with myasthenia gravis? a. Deposition of immune complexes in the muscles b. Binding of antibody to a receptor on muscle cells c. Release of histamine from mast cells in the muscles d. Muscle cell destruction by cytotoxic T cells
b. Binding of antibody to a receptor on muscle cells
Which of the following techniques uses RNA-guided enzymes? a. Microarray b. CRISPR c. Immunohistochemistry d. Restriction fragment mapping
b. CRISPR
What is the immune mechanism involved in type III hypersensitivity reactions? a. Cellular antigens are involved b. Deposition of immune complexes occurs in antibody excess c. Only heterologous antigens are involved d. Tissue damage results from complement-mediated lysis
b. Deposition of immune complexes occurs in antibody excess
In a heterogeneous enzyme immunoassay, if the patient sample produces more signal than the highest positive control, what action should be taken? a. Report the results out as determined b. Dilute the patient sample c. Repeat the immunoassay using one-half the volume of the patient sample d. Report the results as falsely positive
b. Dilute the patient sample
An ELISA assay was performed on a patient's serum sample. What is the relationship of the amount of enzyme activity to the amount of patient analyte measured? a. Indirectly proportional b. Directly proportional
b. Directly proportional
Which isotype of immunoglobulin is involved in a type I hypersensitivity? a. IgA b. IgE c. IgM d. IgG
b. IgE
Reactions involving IgG may need to be enhanced for which reason? a. IgG is only active at 25°C b. IgG may be too small to produce lattice formation c. IgG has only one antigen-binding site d. IgG is only able to produce visible precipitation reactions
b. IgG may be too small to produce lattice formation
Which assay format has the lowest equipment cost? a. Chemiluminescence b. Immunochromatography c. Fluorescence polarization d. Enzyme immunoassay
b. Immunochromatography
How does immunoturbidimetry differ from nephelometry? a. Immunoturbidimetry measures the increase in light after it passes through a solution b. Nephelometry measures light that is scattered at an angle c. Immunoturbidimetry deals with univalent antigens only d. Nephelometry is not affected by large particles falling out of solution
b. Nephelometry measures light that is scattered at an angle
Which of the following is true of the enzyme-multiplied immunoassay technique (EMIT)? a. It is classified as a heterogeneous method b. Nicotinamide adenine dinucleotide (NAD+) is a substrate used in the test reaction c. When the patient sample antigen concentration is high, the final test signal will be low d. Patient sample antigen blocks the enzyme active site in the test reaction
b. Nicotinamide adenine dinucleotide (NAD+) is a substrate used in the test reaction
In an indirect ELISA, what would be the outcome of an improper wash after the antibody-enzyme conjugate is added? a. Results will be falsely decreased b. Results will be falsely increased c. Results will be unaffected d. No wash step is required in the ELISA procedure
b. Results will be falsely increased
Agglutination inhibition could best be used for which of the following types of antigens? a. Large cellular antigens, such as erythrocytes b. Soluble haptens c. Bacterial cells d. Coated latex particles
b. Soluble haptens
Which of the following is characteristic of the endpoint method of RID? a. Readings are taken before equivalence b. The antigen concentration is directly in proportion to the square of the ring diameter c. The ring diameter is plotted against the log of the concentration d. It is primarily a qualitative rather than a quantitative method
b. The antigen concentration is directly in proportion to the square of the ring diameter
Which statement best describes rapid immunochromatographic assays? a. Test results are always reported as quantitative values b. They are designed primarily for point-of-care testing c. Urine is the only acceptable sample type d. Formation of a colored line always indicates a positive result
b. They are designed primarily for point-of-care testing
What is the function of restriction endonucleases? a. They splice short DNA pieces together b. They cleave DNA at specific sites c. They make RNA copies of DNA d. They make DNA copies from RNA
b. They cleave DNA at specific sites
Coombs reagent is used for what purpose? a. To enhance agglutination with IgM-coated red blood cells b. To enhance agglutination with IgG-coated red blood cells c. To cause a precipitation reaction with small amounts of antibody d. To link small antigens on patient red cells
b. To enhance agglutination with IgG-coated red blood cells
In a noncompetitive ELISA, if a negative control shows the presence of signal, which of the following might be a possible explanation? a. No reagent was added b. Washing steps were incomplete c. The enzyme was inactivated d. No substrate was present
b. Washing steps were incomplete
When soluble antigens diffuse in a gel that contains antibody, in which zone does optimum precipitation occur? a. Prozone b. Zone of equivalence c. Postzone d. Prezone
b. Zone of equivalence
All of the following are associated with type I hypersensitivity except: a. release of preformed mediators from mast cells b. activation of complement c. cell-bound antibody bridged by antigen d. an inherited tendency to respond to allergens
b. activation of complement
Two days after administration of the tuberculin skin test, a female health-care worker developed an area of redness and induration 12mm in size at the injection site. This result means that she has a. an active case of TB b. been exposed to M. tuberculosis c. developed protective immunity against TB d. a result in the normal range for her risk group
b. been exposed to M. tuberculosis
Quenching of the signal emitted by the label is of particular concern in: a. radioimmunoassay b. chemiluminescent immunoassays c. fluorescence polarization d. enzyme immunoassay
b. chemiluminescent immunoassays
When a patient's red blood cells combine with anti-A typing serum to produce a positive result, this reaction is known as: a. reverse passive agglutination b. hemagglutination c. passive agglutination d. flocculation
b. hemagglutination
An antigen is fixed to a microscope slide, then incubated with patient serum. After washing, fluorescently labeled anti-human immunoglobulin is applied. After an additional wash, the slide is inspected with a fluorescent microscope. This technique is called: a. autofluorescence b. indirect immunofluorescence c. direct immunofluorescence d. fluorescence polarization
b. indirect immunofluorescence
Which of the following best describes homogeneous assays? a. The concentration of patient antigen is always directly proportional to the label detected b. The reagent antibody has an enzyme tag c. A washing step is not necessary d. Labeled and unlabeled analyte are present in equal amounts
c. A washing step is not necessary
Which of the following is a general characteristic of hypersensitivity reactions? a. The immune responsiveness is depressed b. Antibodies are involved in all reactions c. An exaggerated immune response to an antigen occurs d. The antigen triggering the reaction is a harmful one
c. An exaggerated immune response to an antigen occurs
Which of the following conclusions can be drawn about a patient whose total IgE level was determined to be 150 IU/mL? a. The patient definitely has allergic tendencies b. The patient may be subject to anaphylatic shock c. Antigen-specific testing should be done d. The patient will never have an allergic reaction
c. Antigen-specific testing should be done
If a single IgM molecule can bind many more antigens than a molecule of IgG, which of the following is higher? a. Affinity b. Initial force of attraction c. Avidity d. Initial sensitization
c. Avidity
Which of the following is characteristic of an indirect enzyme immunoassay? a. The first antibody has the enzyme label b. Only one antibody is required c. Color is directly proportional to the amount of patient antibody present d. Enzyme specificity is not essential
c. Color is directly proportional to the amount of patient antibody present
What is the immune phenomenon associated with the Arthus reaction? a. Tissue destruction by cytotoxic T cells b. Removal of antibody-coated RBCs c. Deposition of immune complexes in blood vessels d. Release of histamine from mast clls
c. Deposition of immune complexes in blood vessels
In a precipitation reaction, how can the ideal antibody be characterized? a. Low affinity and low avidity b. High affinity and low avidity c. High affinity and high avidity d. Low affinity and high avidity
c. High affinity and high avidity
In the rheumatoid factor test, what is being detected? a. antithyroglobulin antibody b. IgG directed against IgM c. IgM directed against IgG d. antinuclear antibody
c. IgM directed against IgG
Which of the following correctly describes reverse passive agglutination? a. It is a negative test b. It can be used to detect autoantibodies c. It is used for identification of antigens d. It is used to detect sensitization of RBCs
c. It is used for identification of antigens
Blood was drawn from a 25-year-old woman with suspected SLE. A FANA screen was performed, and a speckled pattern resulted. Which of the following actions should be taken next? a. Report out as diagnostic for SLE b. Report out as drug-induced lupus c. Perform an assay for specific ANAs d. Repeat the test
c. Perform an assay for specific ANAs
A 33-year-old female presents with eyes that have been red and irritated for the past month. Discharge from the eyes is not apparent. She also has a recurrent low-grade fever and a rash on her chest and legs. Her joints have been achy for the past few months, and her mouth has been so dry it is often difficult to swallow food. Antinuclear antibody testing is performed, and a speckled pattern is observed on HEp-2 cells. Which follow-up test result would you expect for this patient? a. Presence of antibody to dsDNA b. Decreased rheumatoid factor c. Presence of anti-SS-A or anti-SS-B d. Positive ANCA
c. Presence of anti-SS-A or anti-SS-B
Anti-mitochondrial antibodies are strongly associated with which disease? a. Autoimmune hepatitis b. Celiac disease c. Primary biliary cholangitis d. Anti-glomerular basement membrane disease
c. Primary biliary cholangitis
Which of the following statements accurately describes heterogeneous competitive binding immunoassays? a. Excess binding sites for the analyte are provided b. Test signal is generated in solution without the need of a solid-phase support material c. The concentration of patient analyte is inversely proportional to bound label d. All the patient analyte is bound in the reaction
c. The concentration of patient analyte is inversely proportional to bound label
Which best describes the law of mass action? a. Once antigen-antibody binding takes place, it is irreversible b. The equilibrium constant depends only on the forward reaction c. The equilibrium constant is related to the strength of antigen-antibody binding d. If an antibody has a high avidity, it will dissociate from antigen easily
c. The equilibrium constant is related to the strength of antigen-antibody binding
Which of the following is characteristic of direct fluorescence immunoassays? a. The anti-immunoglobulin has the fluorescent tag b. Antibody is attached to a solid phase c. This method can be used for rapid identification of microbial antigens d. The amount of color is inversely proportional to the amount of antigen present
c. This method can be used for rapid identification of microbial antigens
Cold autoimmune hemolytic anemia is an example of which type of hypersensitivity? a. Type IV b. Type I c. Type II d. Type III
c. Type II
The process by which particulate antigens such as cells aggregate to form larger complexes when specific antibody is present is called: a. precipitation b. flocculation c. agglutination d. sensitization
c. agglutination
Epitope spreading refers to: a. post-translational modifications to self-antigens b. modifications in gene expression that are not caused by changes in DNA sequence c. expansion of the immune response to unrelated antigens d. cross-reaction of the immune response to a pathogen with a similar self-antigen
c. expansion of the immune response to unrelated antigens
To determine a cold agglutinin titer, a. patient serum should be separated from whole blood at 4°C and tested at 4°C b. patient serum should be separated from whole blood at 4°C and tested at 37°C c. patient serum should be separated from whole blood at 37°C and tested at 4°C d. patient serum should be separated from whole blood at 37°C and tested at 37°C
c. patient serum should be separated from whole blood at 37°C and tested at 4°C
T-cell-dependent hypersensitivity occurs: a. 5-7 days after contact with antigen b. Immediately after exposure to the antigen c. 1 to 4 hours after contact with antigen d. 24 to 72 hours after exposure to the antigen
d. 24 to 72 hours after exposure to the antigen
Which of the following best characterizes chemiluminescent immunoassays? a. Only the antigen can be labeled b. Tests can be read manually c. These are only homogeneous immunoassays d. A chemical is oxidized to produce light
d. A chemical is oxidized to produce light
The purified protein derivative reaction to determine exposure to tuberculosis is based on which of the following? a. An immediate hypersensitivity reaction b. Formation of antigen-antibody complexes c. A type II hypersensitivity reaction d. A sensitized T-cell response
d. A sensitized T-cell response
For which of the following tests is a lack of agglutination a positive reaction? a. Hemagglutination b. Passive agglutination c. Reverse passive agglutination d. Agglutination inhibition
d. Agglutination inhibition
A technologist performs an IIF test for ANCAs and observes that there is an intense fluorescent staining of the nuclear lobes of the neutrophils. How can this type of staining be differentiated from an ANA? a. Perform the test on formalin-fixed leukocytes b. Perform IIF with HEp-2 cells c. Perform an ELISA for ANCAs d. All of the above
d. All of the above
Immunofluorescence assays may be difficult to interpret for which reason? a. Autofluorescence of substances in serum b. Nonspecific binding to serum proteins c. Subjectivity in reading results d. All of the above
d. All of the above
Which of the following statements applies to rate nephelometry? a. Readings are taken before equivalence is reached b. It is more sensitive than immunoturbidimetry c. Measurements are time dependent d. All of the above apply
d. All of the above apply
A speckled pattern of staining of the nucleus on IIF may be caused by which of the following antibodies? a. Anti-dsDNA b. Antibody to histones c. Centromere antibody d. Anti-SS-A/Ro antibody
d. Anti-SS-A/Ro antibody
Which of the following is diagnostic for systemic lupus erythematosus? a. Anti-myelin basic protein antibody b. Anti-insulin antibody c. Anti-EB antibody d. Anti-Sm antibody
d. Anti-Sm antibody
Which of the following would cause a positive DAT test? a. Presence of IgG on RBCs b. Presence of C3b or C3d on RBCs c. A transfusion reaction caused by preformed antibody d. Any of the above
d. Any of the above
Which of the following responses characterizes a capture or sandwich enzyme immunoassay? a. Less anaytically sensitive than competitive enzyme immunoassays b. Labeled antigen attached to a solid phase c. Best for small antigens with a single epitope determinant d. Excess number of antibody sites on solid-phase material
d. Excess number of antibody sites on solid-phase material
Select the technique that would most likely be used to determine the concentration of a therapeutic drug. a. Enzyme immunoassay b. Chemiluminescent assay c. Radioimmunoassay d. Fluorescence polarization immunoassay
d. Fluorescence polarization immunoassay
Which of the following would be considered an organ-specific autoimmune disease? a. SLE b. RA c. GPA d. Hashimoto's thyroidititis
d. Hashimoto's thyroidititis
Extremely high analyte concentrations can cause false-negative results (hook effect) in which type of assay? a. Homogeneous competitive b. Heterogeneous competitive c. Homogeneous noncompetitive d. Heterogeneous noncompetitive
d. Heterogeneous noncompetitive
In vitro methods to detect a cell-mediated response to M. tuberculosis measure production of which of the following immunologic components? a. IgE antibody b. Interleukin-1 c. Interleukin-2 d. Interferon gamma
d. Interferon gamma
Which of the following is a mechanism used to achieve peripheral tolerance? a. Negative selection of autoreactive T cells in the thymus b. Apoptosis of autoreactive B cells in the bone marrow c. Editing of B-cell receptors that weakly recognize self-antigens in the bone marrow d. Lack of a costimulatory signal to autoreactive T cells in the lymph nodes
d. Lack of a costimulatory signal to autoreactive T cells in the lymph nodes
A patient's serum sample is added to a solution containing particulate antigen, but no agglutination is observed. What should be done next? a. Report out as a negative test b. Add more particulate antigen c. Read the reaction in dim light d. Perform serial dilutions of the sample
d. Perform serial dilutions of the sample
Precipitation differs from agglutination in which way? a. Precipitation can only be measured by an automated instrument b. Precipitation occurs with univalent antigen, whereas agglutination requires multivalent antigen c. Precipitation does not readily occur because few antibodies can form aggregates with antigen d. Precipitation involves a soluble antigen, whereas agglutination involves a particulate antigen
d. Precipitation involves a soluble antigen, whereas agglutination involves a particulate antigen
SLE can be distinguished from RA on the basis of which of the following? a. Joint pain b. Presence of Anti-nuclear antibodies c. Immune complex formation with activation of complement d. Presence of anti-dsDNA antibodies
d. Presence of anti-dsDNA antibodies
Which condition would result in hemolytic disease of the fetus and newborn? a. Buildup of IgE on mother's cells b. Sensitization of cytotoxic T cells c. Exposure to antigen found on both mother and baby RBCs d. Prior exposure to foreign RBC antigen
d. Prior exposure to foreign RBC antigen
The speed at which nucleic acids migrate in gel electrophoresis is determined by which property? a. Charge b. Fluorescence c. Absorption d. Size
d. Size
If crossed lines result in an Ouchterlony immunodiffusion reaction with antigens 1 and 2, what does this indicate? a. Antigens 1 and 2 are identical b. Antigen 2 is simpler than antigen 1 c. Antigen 2 is more complex than antigen 1 d. The two antigens are unrelated
d. The two antigens are unrelated
Reactions to latex are caused by a. type I hypersensitivity. b. type IV hypersensitivity. c. skin irritation. d. all of the above.
d. all of the above
A young woman developed red, itchy papules on her wrist 2 days after wearing a new bracelet. This reaction was caused by: a. IgE-sensitized mast cells in the skin b. antigen-antibody complexes in the skin c. damage to the skin cells by antibodies and complement d. an inflammatory response induced by cytokines released from Th1 cells
d. an inflammatory response induced by cytokines released from Th1 cells
A radial immunodiffusion test is run for 72 hours. The concentration of the antigen is then calculated using the: a. log of the diameter of the precipitation ring b. diameter of the precipitation ring c. radius of the precipitation ring d. square of the diameter of the precipitation ring
d. square of the diameter of the precipitation ring