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WorksheetsIS PREFINAL EXAM
Total questions: 95
Worksheet time: 1hrs 4mins
In the interpretation of agglutination tests for febrile diseases, which of the following is of the greatest diagnostic importance?
anamnestic reactions caused by heterologous antigens
rise in titer of the patient's serum
history of previous vaccination
naturally occurring antibodies prevalent where the disease is endemic
Which test has the greatest sensitivity for antigen detection?
precipitin
agglutination
ELISA
complement fixation
The most sensitive procedure for detection of hepatitis B surface antigen (HBsAg) is:
hemagglutination
counterimmunoelectrophoresis
radial immunodiffusion
ELISA
A child has severe hay fever. A total IgE measurement was performed by the Ouchterlony immunodiffusion method. No lines of precipitation appeared on the immunodiffusion plate. The most likely explanation is:
IgE antibodies are not produced in children who have hay fever.
Hay fever is mediated by the cellular system
IgE is in too low a concentration to be detected by this method.
IgA is the antibody commonly produced in people with hay fever.
The serologic test that can be modified to selectively detect only specific IgM antibody in untreated serum is:
complement fixation
immunofluorescence
hemagglutination inhibition
passive hemagglutination
In an indirect (sandwich) ELISA method designed to detect antibody to the rubella virus in patient serum, the conjugate used should be:
anti-human IgG conjugated to an enzyme
antirubella antibody conjugated to an enzyme
rubella antigen conjugated to an enzyme
antirubella antibody conjugated to a substrate
When testing a patient for HIV antibody, which of the following is used to confirm a positive screening test?
radioimmunoassay
Western blot
immunofluorescence
ELISA
What is the immunologic method utilized in the flow cytometer?
latex agglutination
enzyme linked immunoassay
immunofluorescence
radioimmunoassay
The visible serologic reaction between soluble antigen and its specific antibody is:
sensitization
precipitation
agglutination
opsonization
The enzyme-linked immunosorbent assay (ELISA) technique for the detection of HBsAg:
requires radiolabeled C lq
is quantitated by degree of fluorescence
uses anti-HBs linked to horseradish peroxidase
uses beads coated with HBsAg
The detection of precipitation reactions depends on the presence of optimal proportions of antigen and antibody. A patient’s sample contains a large amount of antibody, but the reaction in a test system containing antigen is negative. What has happened?
Performance error
Low specificity
A shift in the zone of equivalence
Prozone phenomenon
Which part of the radial immunodiffusion (RID) test system contains the antisera/antibody?
Center well
Outer wells
Gel
Antisera may be added to any well
What is the interpretation when an Ouchterlony plate shows crossed lines between wells 1 and 2 (antigen is placed in the center well and antisera in wells 1 and 2)?
No reaction between wells 1 and 2
Partial identity between wells 1 and 2
Nonidentity between wells 1 and 2
Identity between wells 1 and 2
Why is a chemiluminescent immunoassay (CIA) or enzyme immunoassay (EIA) the method of choice for detection of certain analytes, such as hormones, normally found in low concentrations?
Because of low cross reactivity
Because of high specificity
Because of high sensitivity
Because test systems may be designed as both competitive and noncompetitive assays
Which of the following describes an antigen-antibody precipitation reaction of nonidentity ?
precipitin lines cross, forming double spurs
precipitin lines fuse, forming a single spu
no precipitin lines are formed
precipitin lines fuse, forming a single arc
Which is a recognized theory of the origin of autoimmunity?
enhanced suppressor T-cell function
diminished helper T-cell activity
defects in the idiotype-anti-idiotype network
deficient B-cell activation
A technologist who observes a red rash on her hands after
removing her gloves
should apply antimicrobial lotion to the hands
may be washing the hands too frequently.
may have developed a latex allergy
should not create friction when washing the hands.
In the chain of infection, a contaminated work area would serve as which of the following?
Source
Method of transmission
Host
All of the above
The Occupational Exposure to Bloodborne Pathogens Standard developed by OSHA requires employers to
provide all of the following except
hepatitis B immunization
safety training
hepatitis C immunization
laundry facilities for non-disposable lab coats
An employee who receives an accidental needlestick
should immediately
apply sodium hypochlorite to the area
notify a supervisor
receive HIV prophylaxis
receive a hepatitis B booster shot
The first thing to do when acid is spilled on the skin is to
notify a supervisor
neutralize the area with a base
apply burn ointment
flush the area with water
A technician who is pregnant should avoid working with
organic chemicals
radioisotopes
HIV-positive serum
needles and lancets
In a precipitation reaction, how can the ideal antibody
be characterized?
Low affinity and low avidity
High affinity and low avidity
High affinity and high avidity
Low affinity and high avidity
Precipitation differs from agglutination in which way?
Precipitation can only be measured by an automated
instrument
Precipitation occurs with univalent antigen, while agglutination requires multivalent antigen
Precipitation does not readily occur, because few antibodies can form aggregates with antigen
Precipitation involves a soluble antigen, while agglutination involves a particulate antigen
When soluble antigens diffuse in a gel that contains antibody, in which zone does optimum precipitation occur?
Prozone
Zone of equivalence
Postzone
Prezone
Which of the following statements apply to rate
nephelometry
Readings are taken before equivalence is reached.
It is more sensitive than turbidity
Measurements are time dependent
All of the above
Which of the following is characteristic of the end-point method of Radial Immunodiffusion?
Readings are taken before equivalence
Concentration is directly in proportion to the square of the diameter
The diameter is plotted against the log of the concentration
It is primarily a qualitative rather than a quantitative method
Which statement is true of measurements of turbidity?
It indicates the ratio of incident light to transmitted light
Light that is scattered at an angle is detected
It is recorded in units of relative light scatter
It is not affected by large particles falling out of solution.
Which of the following refers to the force of attraction
between an antibody and a single antigenic determinant?
Affinity
Avidity
Van der Waals attraction
Covalence
Which technique is typified by radial immunodiffusion combined with electrophoresis?
Countercurrent electrophoresis
Rocket electrophoresis
Immunoelectrophoresis
Southern blotting
Immunofixation electrophoresis differs from immunoelectrophoresis in which way?
Electrophoresis takes place after diffusion has occurred.
Better separation of proteins with the same electrophoretic mobilities is obtained
Antibody is directly applied to the gel instead of being placed in a trough
It is mainly used for antigen detection
In which zone might an antibody-screening test be false
negative?
Prozone
Zone of equivalence
Postzone
None of the above
If crossed lines result in an Ouchterlony immunodiffusion reaction with antigens 1 and 2, what does this indicate?
Antigens 1 and 2 are identical
Antigen 2 is simpler than antigen 1.
Antigen 2 is more complex than antigen 1.
The two antigens are unrelated
Which might affect the outcome of immunodiffusion procedures?
Improper dilution of antigen in the wells
Overfilling the wells
Nonlevel incubation of plates
All of the above
Which technique represents a single-diffusion reaction?
Radial immunodiffusion
Ouchterlony diffusion
Immunoelectrophoresis
All of the above
Which best describes the law of mass action?
Once antigen–antibody binding takes place, it is irreversible.
The equilibrium constant depends only on the forward reaction
The equilibrium constant is related to strength of antigen antibody binding.
If an antibody has a high avidity, it will dissociate from antigen easily
Which of the following best describes agglutination?
A combination of soluble antigen with soluble antibody
A combination of particulate antigen with soluble antibody
A reaction that produces no visible end point
A reaction that requires instrumentation to read
All of the following could be used to enhance an agglutination reaction except
increasing the viscosity of the medium
using albumin
increasing the ionic strength of the medium
centrifugation
Agglutination of dyed bacterial cells represents which type of reaction?
Direct agglutination
Passive agglutination
Reverse passive agglutination
Agglutination inhibition
In which of the following circumstances would the indirect Coombs’ test be employed?
Identification of the ABO blood groups
Identification of cold-reacting antibody
Identification of an unexpected IgG antibody
Identification of hemolytic disease of the newborn
In an agglutination reaction, if cells are not centrifuged
long enough, which of the following might occur?
False-negative result
False-positive result
No effect
Slight effect but can be ignored
Agglutination inhibition could best be used for which of the following types of antigens
Large cellular antigens such as erythrocytes
Soluble haptens
Bacterial cells
Antigen attached to latex particles
Which of the following correctly describes reverse passive agglutination?
It is a negative test
It can be used to detect autoantibodies.
It is used for identification of bacterial antigens
It is used to detect sensitization of red blood cells.
In which of the following tests is patient antigen determined by measuring the number of non-agglutinating particles left after the reaction has taken place?
Direct agglutination
Coagglutination
PACIA
Coombs’ testing
Reactions involving IgG may need to be enhanced for which reason?
It is only active at 25°C.
It may be too small to produce lattice formation
It has only one antigen-binding site
It is not able to produce visible in vitro agglutination
For which of the following tests is a lack of agglutination a positive reaction?
Hemagglutination
Passive agglutination
Reverse passive agglutination
Agglutination inhibition
All of the following would be considered good quality control procedures except
storing reagents properly
standardizing temperature of reactions
allowing the reaction to go as long as possible
using monoclonal antibody to avoid cross-reactivity
A positive direct antiglobulin/Coombs’ test could occur under which circumstances?
Hemolytic disease of the newborn
Autoimmune hemolytic anemia
Antibodies to drugs that bind to red cells
Any of the above
Which of the following statements accurately describes competitive binding assays?
Excess binding sites for the analyte are provided.
Labeled and unlabeled analyte are present in equal amounts.
The concentration of patient analyte is inversely proportional to bound radioactive label.
All the patient analyte is bound in the reaction.
How do heterogeneous assays differ from homogeneous assays?
Heterogeneous assays require a separation step.
Heterogeneous assays are easier to perform than homogeneous assays.
The concentration of patient analyte is directly proportional to bound label in homogeneous assays.
Homogeneous assays are more sensitive than heterogeneous ones.
Which of the following characterizes a capture or sandwich
enzyme assay?
Less sensitive than competitive enzyme assays
Requires two wash steps
Best for small antigens with a single determinant
Best for small antigens with a single determinant
Advantages of EIA over RIA include all except which one
of the following?
Decrease in hazardous waste
Shorter shelf life of kit
No need for expensive equipment
Ease of adaptation to automated techniques
Which of the following is characteristic of direct fluorescent
assays?
The anti-immunoglobulin has the fluorescent tag.
Antibody is attached to a solid phase
Microbial antigens can be rapidly identified by this method.
The amount of color is in inverse proportion to the amount of antigen present.
Which of the following is true of fluorescence polarization
immunoassay?
Both antigen and antibody are labeled.
Large molecules polarize more light than smaller molecules.
When binding occurs, there is quenching of the fluorescent tag.
The amount of fluorescence is directly proportional to concentration of the analyte.
All of the following are desirable characteristics of antibodies used in immunoassays except
high affinity
high specificity
high cross-reactivity
not found in the patient sample
Which of the following best characterizes chemiluminescent assays?
Only the antigen can be labeled
Tests can be read manually
These are only homogeneous assays
A chemical is oxidized to produce light
Immunofluorescent assays may be difficult to interpret
for which reason?
Autofluorescence of substances in serum
Nonspecific binding to serum proteins
Subjectivity in reading results
Any of the above
Which statement best describes flow-through immunoassays?
Results are quantitative
Reagents must be added separately.
They are difficult to interpret.
They are designed for point-of-care testing
How are DNA and RNA different?
Only RNA contains uracil.
Only DNA contains cytosine.
DNA is less stable than RNA
RNA is usually double-stranded
All of the following would be advantages of nucleic acid amplification techniques except
detection of nonviable organisms.
extreme sensitivity.
early detection of disease.
low cost.
What is PCR used for in clinical settings?
Detection of early HIV infection
Determination of specific HLA antigens
Measurement of cytokines
All of the above
During PCR, what happens in the annealing step?
The primers bind to the target DNA.
Strands are separated by heating
An RNA copy is made.
Protein is made from the DNA strands
Which best describes the PCR?
Two probes are joined by a ligating enzyme
RNA copies of the original DNA are made
Extender probes are used to detect a positive reaction
Primers are used to make multiple DNA copies
Characteristics of the acquired IS include:
Immediate defense mechanism
Lack of an inflammatory response
Production of antibody and lymphokines
Primary and secondary responses being the same
Substances that participate in the regulation of the immune response are called:
Haptens
Haptoglobin
Cytokines
Lysozymes
Which cell is identified primarily by the presence of immunoglobulin on its surface?
Neutrophil
NK cell
B cell
Monocyte
Which cell functions primarily in antigen processing and presentation?
TC cell
Macrophage
Plasma cell
NK cell
Which complement factor is common to both classic and alternative pathways and will result in formation of the MAC?
Factor B
Factor C3
Factor C1
Factor C4
Which of the following patient samples for blood bank testing is most likely to contain active complement?
EDTA-anticoagulated sample
Heparin-anticoagulated sample
Serum sample drawn 2 days ago
Serum sample drawn 2 hours ago
Which antibody is produced rapidly and in highest amounts during secondary response?
IgG
IgM
IgA
Both IgM and IgG
Monoclonal antibodies
Have specificity for a single epitope
May be manufactured using hybridoma technology
Develop from a single B-cell clone
All of the above
None of the above
A cellular product is irradiated to prevent the transfusion of viable lymphocytes to an immunocompromised patient. What type of reaction is prevented by this action
Type I, anaphylaxis
Type II, transfusion reaction
Type III, immune complex formation
Type IV, graft-versus-host reaction
Secreted IgA exists as a:
Monomer only
Dimer only
Trimer only
Both monomeric and polymeric forms
IgM antibody has 10 antigen-binding sites but its valency is:
Pentameric
Twofold pentameric
Trimeric
Hexameric
Circulating C1 macromolecule complement protein complex consists of which three proteins?
C1q, C1r, C1s
C1q, C2q, C3q
C1q-a, C1r-a, C1s-a
C1q, C5r, C9s and properdin
Which complement proteins are good at initiating inflammation?
C1q, C1r, C1s
C3a and C5a
C4a
C3b and C5b
Mannose-binding protein in the lectin pathway is most
similar to which classical pathway component?
C3
C1rs
C1q
C4
Which of the following describes the role of properdin in the alternative pathway?
Stabilization of C3/C5 convertase
Conversion of B to Bb
Inhibition of C3 convertase formation
Binding to the initiating antigen
All of the following represent functions of the complement system except
decreased clearance of antigen–antibody complexes
lysis of foreign cells
increase in vascular permeability
migration of neutrophils to the tissues
A lack of CR1 receptors on red blood cells would result in which of the following?
Decreased binding of C3b to red blood cells
Lack of clearance of immune complexes by the spleen
Increased breakdown of C3b to C3d and C3g
All of the above
SLE can be distinguished from RA on the basis of which of the following?
Joint pain
Presence of antinuclear antibodies
Immune complex formation with activation of complement
Presence of anti-ds DNA antibodies
PCR technology can be used to:
Amplify small amounts of DNA
Isolate intact nuclear RNA
Digest genomic DNA into small fragments
Repair broken pieces of DNA
Transcription can be defined as
Introduction of DNA into cultured cells
Reading of mRNA by the ribosome
Synthesis of RNA using DNA as a template
Removal of external sequences to form a mature RNA molecule
When a man possesses a phenotypic trait that he passes to all his daughters and none of his sons, the trait is said to be:
X-linked dominant
X-linked recessive
Autosomal dominant
Autosomal recessive
When a woman possesses a phenotypic trait that she passes to all of her sons and none her daughters, the trait is said to be:
X-linked dominant
X-linked recessive
Autosomal dominant
Autosomal recessive
DNA is replicated
Semi-conservatively from DNA
In a random manner from RNA
By copying protein sequences from RNA
By first copying RNA from protein
RNA is processed:
After RNA is copied from DNA template
After protein folding and unfolding on the ribosome
Before DNA is copied from DNA template
After RNA is copied from protein on ribosomes
Translation of proteins from RNA takes place:
On the ribosomes in the cytoplasm of the cell
On the nuclear membrane
Usually while attached to nuclear pores
Inside the nucleolus of the cell
Which of the following is the most common humoral immune deficiency disease?
BrutomAgammaglobulinemia
IgG deficiency
Wiskott Aldrich syndrome
Selective IgA deficiency
Antigen determinant is called _____ while antibody determinant is termed _____.
Paratope, Epitope
Epitope, Paratope
Valence, Epitope
None of these
A combination of electrophoresis and double immunodiffusion is referred to as?
immunoelectrophoresis
double radial diffusion
immunofluorescence
electroimmunodiffusion
In primary biliary cirrhosis, which of the following antibodies are seen?
antimitochondrial antibodies
anti-smooth muscle antibodies
anti-parietal cells antibody
anti-DNA antibodies
Which of the following are the antibodies seen in chronic active hepatitis?
antimitochondrial antibodies
anti-smooth muscle antibodies
anti-parietal cells antibody
anti-DNA antibodies
OX-2 OX-19 and OX-K are antigens of?
Rickettsia
Proteus
Leptospira
Salmonella
The Hinge region in an immunoglobulin is located between which domains?
CH3 and VL
CH3-CH4
CH1-CH2
CH2-CH3
