Immunology & Serology Part 3 Feedback

Selective lgA deficiency is the most common

immunodeficiency.

Patients suffering from Waldenstrom macroglo Untitled Section

bulinemia demonstrate excessively increased
2 of 2 points
concentrations of which of the following?

*
Which of the following is a true statement
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about Bruton agammaglobulinemia?
IgG
*
IgA
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IgM
It is found only in females

There are normal numbers of circulating B cells

IgD
There are decreased to absent concentrations of
Feedback immunoglobulins

Waldenstrom macroglobulinemia is a
monoclonal gammopathy in which the tumor
The disease presents with pyogenic infections 1
cells are making lgM. The uncontrolled secretion
week after birth
of such a high molecular weight compound
causes a severe increase in viscosity. Feedback
Untitled Section Bruton agammaglobulinemia is an X-linked
disease (therefore, usually found in males) in
2 of 2 points
which there is a decreased immunoglobulin
concentration, which becomes apparent at 2-6
months of age, ie, after the infant's maternally-
Which of the following is the
transferred immunoglobulin has decreased due
most common humoral immune deficiency
to its biological half-life. Problem is in
disease?
differentiation at the pre-B-cell stage.
*
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0 of 2 points
Bruton agammaglobulinemia

Selective lgA deficiency

Combined immunodeficiency disease with loss
of muscle coordination is referred to as:

Wiskott-Aldrich syndrome *

lgG deficiency 0/2

DiGeorge syndrome *

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Bruton agammaglobulinemia Undetectable hemolytic complement activity in

the serum
Ataxia telangiectasia
Systemic lupus erythematosus
Wiskott-Aldrich syndrome
No detectable disease
Correct answer
A lifelong history of life-threatening infections
Ataxia telangiectasia

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X-linked infantile agammaglobulinemia is
Bruton agammaglobulinemia; DiGeorge C3 deficiency is the worst deficiency to have; it
syndrome is a T-cell deficiency; Swiss-type is a causes a lifelong history of life-threatening
SCID; ataxia has additional muscular infections.
coordination problems.

Untitled Section
Hereditary deficiency of late complement
4 of 6 points components (C5, C6, C7 or CS) can be
associated with which of the
following conditions?
Hereditary deficiency of early complement
*
components (C1, C4 and C2) is associated with:
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*
Pneumococcal septicemia
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Pneumococcal septicemia
Small bowel obstruction
Small bowel obstruction
Systemic lupus erythematosus
Lupus erythematosus like syndrome
Systemic Neisseria infection if exposed

Correct answer
Gonococcemia
Systemic Neisseria infection if exposed
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C1, C4, C2 deficiencies are associated with a
lupus erythematosus-like syndrome. C5, C6, C7, C8 deficiencies are associated with a
more severe Neisseria infection if the patient is
exposed due to less pathogen clearance.
Which of the following has been associated with
Untitled Section
patients who have homozygous C3 deficiency?
2 of 2 points
 ELISA is a solid-phase immunoassay that uses
anti-immunoglobulins that are labeled with an
The strength of a visible reaction is known as:
enzyme that can be detected by the appearance
* of color on the addition of a substrate.

2/2 Untitled Section

Prozone reaction 0 of 2 points

Absorption

Avidity The visible serological reaction between soluble

antigen and its specific antibody is:

*
Elution
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Sensitization
Avidity is the sum of the interactions between
all interacting antigen epitopes and Fab sites, Precipitation
and describes the strength of the interaction of
Agglutination
an antibody with its antigen.
Opsonization
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0 of 2 points
Correct answer

Precipitation
Which test has the greatest sensitivity for
antigen detection? Feedback

* Precipitation takes place when antibodies and

soluble antigens are mixed.
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Untitled Section
Precipitin
2 of 2 points

Agglutination
The prozone phenomenon can result in a (an):*
ELISA
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Complement fixation
False-positive reaction
Correct answer
False-negative reaction
ELISA

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Enhanced agglutination
Diminished antigen response 0 of 2 points

Untitled Section

0 of 2 points A substrate is first exposed to a patient’s serum,

then after washing, ANTI-HUMAN
IMMUNOGLOBULIN LABELED WITH A
Which of the following is the most common FLUOROCHROME is added. The procedure
application of IMMUNOELECTROPHORESIS described is:*
(IEP)?*
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Fluorescent quenching
Identification of the absence of a normal serum
Indirect fluorescence
protein
Direct fluorescence

Structural abnormalities of proteins

Fluorescence inhibition
Screening for circulating immune complexes
Correct answer
Diagnosis of monoclonal gammopathies
Indirect fluorescence
Correct answer
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Diagnosis of monoclonal gammopathies
0 of 2 points
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0 of 2 points
BLOCKING TEST in which an antigen is first
exposed to unlabeled antibody and then to
In a ____ immunofluorescent assay, ANTIBODY labeled antibody, and is finally washed and
THAT IS CONJUGATED WITH A FLUORESCENT examined:*
TAG is added directly to unknown antigen that is
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fixed to a microscope slide:*
Direct immunofluorescent assay
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Direct immunofluorescent assay

Indirect immunofluorescent assay
Indirect immunofluorescent assay
Inhibition immunofluorescent assay

Correct answer
Inhibition immunofluorescent assay
Inhibition immunofluorescent assay
Correct answer
Untitled Section
Direct immunofluorescent assay
0 of 2 points
Untitled Section
In FLUORESCENCE POLARIZATION The polymerase chain reaction (PCR) involves
IMMUNOASSAY (FPIA), the degree of three processes. Select the order in which these
fluorescence polarization is ____ proportional occur.*
to concentration of the analyte.*
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Extension→Annealing→Denaturation
Direct
Annealing→Denaturation→Extension
Inverse
Denaturation→Annealing→Extension
Variable

Denaturation→Extension→Annealing
No effect
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Correct answer
The PCR process results in identical copies of a
Inverse piece of double-stranded DNA. The process
involves three steps that are repeated to double
Untitled Section
the number of copies produced with each cycle.
0 of 2 points
The first step is denaturation to separate the
complementary strands.
In FLUORESCENCE POLARIZATION
IMMUNOASSAY (FPIA), labeled antigens Annealing occurs when a primer binds upstream
compete with unlabeled antigen in the patient to the segment of interest on each strand, called
sample for a limited number of antibody binding the template.
sites. The MORE antigen that is present in the
patient sample:* Extension involves the enzymatic addition of
nucleotides to the primer to complete the new
0/2 strand.
Less fluorescence Untitled Section
Greater fluorescence 2 of 2 points
Less fluorescence polarization

Greater fluorescence polarization In the PCR cycle, how is denaturation

accomplished?*

Correct answer 2/2

Less fluorescence polarization Heat

Untitled Section

2 of 2 points Alkali treatment

Addition of sulfonylurea Long-incubation hepatitis

Formamide Hepatitis B surface antigen (HBsAg)

Feedback Hepatitis B core antigen (HBcAg)

In PCR, the separation of dsDNA occurs by Correct answer

heating the sample. This breaks the double
Hepatitis B surface antigen (HBsAg)
bonds between the base pairs and is reversible
by lowering the temperature. Untitled Section
Untitled Section 0 of 2 points
0 of 2 points

The FIRST SEROLOGIC MARKER to appear in

patients with acute hepatitis B virus infection
What temperature is used to achieve DNA
is:*
denaturation to a single strand?*
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Anti-HBs
74 °C

92 °C
Anti-HBc

Anti-HBe
94 °C
HBsAg
102 °C
Correct answer
Correct answer
HBsAg
94 °C
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0 of 2 points
DENATURATION: 94C
ANNEALING: 50 to 58C or higher
EXTENSION: 72C
Which surface marker is a reliable marker for
Untitled Section the presence of high levels of hepatitis B virus
(HBV) and a high degree of infectivity?*
0 of 2 points
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HBeAg
The Australia antigen is now called:*
HBsAg
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Dane particle
HBcAg
Anti-HBsAg Untitled Section

Correct answer 0 of 2 points

HBeAg

Untitled Section If only anti-HBs is positive, which of the

following can be ruled out?*
0 of 2 points
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Hepatitis B virus vaccination

Which of the following tests is positive during
the WINDOW PERIOD of infection with hepatitis Distant past infection with hepatitis B virus
B?*

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Hepatitis B immune globulin (HBIG) injection
Hepatitis B surface antigen
Chronic hepatitis B virus infection
Hepatitis B surface antibody
Correct answer
Hepatitis B core antibody
Chronic hepatitis B virus infection
Hepatitis C antibody
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Persons with chronic HBV infection show a

Correct answer positive test result for anti-HBc (IgG or total)
and HBsAg but not anti-HBs. Patients with
Hepatitis B core antibody
active chronic hepatitis have not become
Untitled Section immune to the virus.

0 of 2 points Untitled Section

2 of 2 points

Which hepatitis antibody confers immunity

against reinfection with hepatitis B virus?*
Risk factors for hepatitis C virus (HCV) include:*
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Anti-HBc IgM
Illegal IV drug use
Anti-HBc IgG
Occupational exposure

Multiple sexual partners

Anti-HBe
All of the above
Anti-HBs

Correct answer
Untitled Section
Anti-HBs
0 of 2 points Kaposi’s sarcoma

The specific diagnostic test for hepatitis C is:* Toxoplasmosis

0/2 Non-Hodgkin’s lymphoma

Absence of anti-HAV and anti-HBsAg Untitled Section

Increase in liver serum enzyme levels 2 of 2 points

Detection of non-A, non-B antibodies Antibodies to which of the following viral

antigens are usually the first to be detected in
Anti-HCV
HIV infection?*
Correct answer
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Anti-HCV
gp120
Untitled Section
gp160
2 of 2 points
gp41

p24
As AIDS progresses, the quantity of _______
diminishes and the risk of opportunistic
infection increases.* Feedback

2/2 In HIV-1 infection, antibodies to the gag proteins

p24 and p55 appear relatively early after
HIV antigen
exposure to the virus, but tend to decrease or
HIV antibody become undetectable as clinical symptoms of
AIDS appear.
CD4+ T lymphocytes
Antibodies to the envelope proteins gp41,
gp120, and gp160 appear slightly later but
CD8+ T lymphocytes remain throughout all disease stages in an HIV-
Untitled Section infected individual, making them a more
reliable indicator of the presence of HIV.
2 of 2 points
Untitled Section

0 of 2 points
The most frequent malignancy observed in AIDS
patients is:*

2/2 The fourth-generation ELISA tests for HIV

detect:*
Pneumocystis jiroveci (P. carinii)
0/2 Bands at p24 and p31

HIV-1 and HIV-2 antigens Bands at p24 and gp120

HIV-1 and HIV-2 antibodies Correct answer

p24 antigen Bands at p24 and gp120

Feedback

HIV-1 and HIV-2 antibodies and p24 antigen Criteria for determining a positive test result
have been published by the Association of State
Correct answer
and Territorial Public Health Laboratory
HIV-1 and HIV-2 antibodies and p24 antigen Directors and CDC, the Consortium for
Retrovirus Serology Standardization, the
Feedback American Red Cross, and the FDA.
FIRST GENERATION
Solid-phase, indirect According to these criteria, a result should be
Anti-HIV1 reported as positive if at least two of the
following three bands are present: p24, gp41,
SECOND GENERATION and gp120/gp160.
Indirect binding Untitled Section
Anti-HIV1, anti-HIV2
2 of 2 points
THIRD GENERATION
Sandwich technique
Anti-HIV1, anti-HIV2 Which part of the radial immunodiffusion (RID)
Simultaneously detecting HIV antibodies of test system contains the antisera?*
different immunoglobulin classes, including IgM
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FOURTH GENERATION Center well
Detects anti-HIV1, anti-HIV2 and p24
Outer wells
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Gel
0 of 2 points

Antisera may be added to any well

Which is most likely a positive Western blot
result for infection with HIV?* Feedback

0/2 In an RID test system, for example, one

measuring hemopexin concentration, the gel
Band at p24 would contain the antihemopexin. A
standardized volume of serum containing the
Band at gp60
antigen is added to each well. Antigen diffuses
from the well into the gel and forms a precipitin
ring by reaction with antibody. At equivalence,
the area of the ring is proportional to antigen Result is impossible to determine
concentration.

Untitled Section
Correct answer
0 of 2 points
Result will be falsely increased

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What is the interpretation when an Ouchterlony
If unbound enzyme-conjugated anti-
plate shows crossed lines between wells 1 and
immunoglobulin is not washed away, it will
2(antigen is placed in the center well and
catalyze conversion of substrate to colored
antisera in wells 1 and 2)?*
product, yielding a falsely elevated result.
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Untitled Section
No reaction between wells 1 and 2
0 of 2 points
Partial identity between wells 1 and 2

What would happen if the color reaction phase

Nonidentity between wells 1 and 2 is prolonged in one tube or well of an ELISA
test?*
Identity between wells 1 and 2
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Correct answer
Result will be falsely decreased
Nonidentity between wells 1 and 2
Result will be falsely increased
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Result will be unaffected
Crossed lines indicate nonidentity between wells
1 and 2. The antibody from well 1 recognizes a
different antigenic determinant than the
Impossible to determine
antibody from well 2.
Correct answer
Untitled Section
Result will be falsely increased
0 of 2 points
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If the color reaction is not stopped within the

What outcome results from improper washing
time limits specified by the procedure, the
of a tube or well after adding the enzyme–
enzyme will continue to act on the substrate,
antibody conjugate in an ELISA system?*
producing a falsely elevated test result.
0/2
Untitled Section
Result will be falsely decreased
0 of 2 points
Result will be falsely increased

Result will be unaffected

The directions for a slide agglutination test Decreased numbers of CD4 T cells.
instruct that after mixing the patient’s serum
Untitled Section
and latex particles, the slide must be rotated for
2 minutes. What would happen if the slide were 2 of 2 points
rotated for 10 minutes?*

0/2
Which CD4:CD8 ratio is most likely in a patient
Possible false-positive result with acquired immunodeficiency syndrome
(AIDS)?*
Possible false-negative result
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No effect
2:1
Depends on the amount of antibody present in
the sample 3:1

2:3
Correct answer 1:2
Possible false-positive result

Feedback Feedback
Failure to follow directions, as in this case where An inverted CD4:CD8 ratio (less than 1.0) is a
the reaction was allowed to proceed beyond the common finding in an AIDS patient. The Centers
recommended time, may result in a false- for Disease Control and Prevention requires a
positive reading. Drying on the slide may lead to CD4-positive (helper T) cell count of less than
a possible erroneous positive reading. 200/μL or 14% in the absence of an AIDS-
defining illness (e.g., Pneumocystis carinii
Untitled Section
pneumonia) in the case surveillance definition of
0 of 2 points AIDS.

Untitled Section

The characteristic laboratory finding in HIV 0 of 2 points

infection is:*

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All of the following hepatitis viruses are spread
Decreased numbers of CD4 T cells. through blood or blood products except:*

Decreased numbers of CD8 T cells. 0/2

Decreased numbers of CD20 B cells. Hepatitis A

Hepatitis B

Decreased immunoglobulins. Hepatitis C

Correct answer Hepatitis D

 for about 3 months after serum enzyme levels
return to normal.
Correct answer
Untitled Section
Hepatitis A
0 of 2 points
Feedback

Hepatitis A is spread through the fecal–oral

route and is the cause of infectious hepatitis. Which is the first antibody detected in serum
Hepatitis A virus has a shorter incubation period after infection with hepatitis B virus (HBV)?*
(2–7 weeks) than hepatitis B virus (1–6 months).
0/2
Epidemics of hepatitis A virus can occur,
especially when food and water become Anti-HBs
contaminated with raw sewage.

Hepatitis E virus is also spread via the oral–fecal Anti-HBc IgM

route and, like hepatitis A virus, has a short
incubation period. Anti-HBe

Untitled Section All are detectable at the same time

0 of 2 points Correct answer

Anti-HBc IgM

Which hepatitis B marker is the best indicator of Feedback

early acute infection?* Antibody to the hepatitis B core antigen (anti-
0/2 HBc) is the first detectable hepatitis B antibody.
It persists in the serum for 1–2 years post-
HBsAg infection and is found in the serum of
HBeAg asymptomatic carriers of HBV.

Anti-HBc Untitled Section

0 of 2 points

Anti-HBs

Correct answer Which test, other than serological markers, is

most consistently elevated in viral hepatitis?*
HBsAg
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Feedback
Antinuclear antibodies
Hepatitis B surface antigen (HBsAg) is the first
marker to appear in hepatitis B virus infection. It Alanine aminotransferase (ALT)
is usually detected within 4 weeks of exposure Absolute lymphocyte count
(prior to the rise in transaminases) and persists
Lactate dehydrogenase 0 of 2 points

Correct answer

Alanine aminotransferase (ALT) When soluble antigens diffuse in a gel that

contains antibody, in which zone does
Feedback
OPTIMUM precipitation occur?*
ALT is a liver enzyme and may be increased in
0/2
hepatic disease. Highest levels occur in acute
viral hepatitis, reaching 20–50 times the upper Prozone
limit of normal.

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Zone of equivalence
0 of 2 points
Postzone

Prezone
In monitoring an HIV-infected patient, which
Correct answer
parameter may be expected to be the most
sensitive indicator of the effectiveness of Zone of equivalence
antiretroviral treatment?*
Untitled Section
0/2
0 of 2 points
HIV antibody titer

Which technique represents a SINGLE-diffusion

CD4:CD8 ratio reaction?*
HIV viral load 0/2
Absolute total T-cell count Radial immunodiffusion
Correct answer Ouchterlony diffusion
HIV viral load

Feedback Immunoelectrophoresis
The HIV viral load will rise or fall in response to Immunofixation electrophoresis
treatment more quickly than any of the other
listed parameters. The absolute CD4 count is Correct answer
also an indicator of treatment effectiveness and Radial immunodiffusion
is used in resource-poor areas that might not
have facilities for molecular testing available. Untitled Section
Note that the absolute CD4 count is not one of 0 of 2 points
the choices, however.

Untitled Section
Reactions involving IgG may need to be Direct hemagglutination
enhanced for which reason?*
Passive hemagglutination
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Hemagglutination inhibition
It is only active at 25°C.

It may be too small to produce lattice formation.

Reverse passive hemagglutination
It has only one antigen-binding site.
Correct answer
It is only able to produce visible precipitation
Direct hemagglutination
reactions.
Untitled Section

2 of 2 points
Correct answer

It may be too small to produce lattice formation.

The serum of an individual who received all
Untitled Section
doses of the hepatitis B vaccine should
0 of 2 points contain:*

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For which of the following tests is a lack of Anti-HBs

agglutination a positive reaction?*

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Anti-HBe
Hemagglutination
Anti-HBc

All of the above

Passive agglutination
Untitled Section
Reverse passive agglutination
2 of 2 points
Agglutination inhibition

Correct answer
The most common means of HIV transmission
Agglutination inhibition worldwide is through:*

Untitled Section 2/2

0 of 2 points Blood transfusions

Intimate sexual contact.

Typing of RBCs with reagent antiserum

represents which type of reaction?*
Sharing of needles in intravenous drug use.
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Transplacental passage of the virus.
Untitled Section Agglutination occurs when the antigen is
particulate
0 of 2 points
Feedback

Precipitation reactions occur between soluble

False-negative test results in a laboratory test
antigen and soluble antibody that produce a
for HIV antibody may occur because of:*
visible end result typically in the form of a visible
0/2 line of precipitate.

Heat inactivation of the serum before testing. Agglutination reactions occur when the antigen
Collection of the test sample before is particulate or coated on a particulate such as
seroconversion. latex beads.

Interference by autoantibodies. Untitled Section

0 of 2 points

Recent exposure to certain vaccines.

Correct answer Postzone causes false-negative reactions in

antibody titers as a result of which of the
Collection of the test sample before following?*
seroconversion.
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Untitled Section
Too much diluent added to test
0 of 2 points

Excess antibody in test

What is the main difference between
agglutination and precipitation reactions?* Excess antigen in test

0/2 Incorrect diluent added to test

Agglutination occurs between a soluble antigen Correct answer

and antibody Excess antigen in test
Agglutination occurs when the antigen is Feedback
particulate
PROZONE
Precipitation occurs when the antigen is Antibody excess, false negative
particulate Remedy: serum dilution
Precipitation occurs when both antigen and
antibody are particulate POSTZONE
Antigen excess, false negative
Remedy: repeat test after a week to give time
Correct answer for antibody production

Untitled Section
2 of 2 points Nephlometry measures light scattered in a
solution, and turbidimetry measures light
transmitted through a solution
Serum tested positive for HBsAg and anti-HBc
Correct answer
IgM. The patient most likely has which of the
following?* Nephlometry measures light scattered in a
solution, and turbidimetry measures light
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transmitted through a solution
Acute hepatitis C
Feedback
Chronic hepatitis B
Nepholometry measures light at angles. The
Acute hepatitis B light source used for detection is placed at an
angle from the detection device.

Acute hepatitis A Turbidometry detection devices are placed

directly across from the light source and
Feedback measures the intensity of the light as it passes
The most likely answer is acute hepatitis B through solution.
because of the presence of IgM anti-HBc in Untitled Section
combination with the hepatitis surface antigen.
Typically the presence of IgM indicates the 0 of 2 points
presence of an acute phase of a disease.

Untitled Section HIV can infect all of the following cells except:*
0 of 2 points 0/2

CD4+ subset of lymphocytes

What is the difference between nephelometry
and turbidimetry?*
Macrophages
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Monocytes
There is no difference between the two assays,
only in name Polymorphonuclear leukocytes

Nephlometry is a newer example of Correct answer

turbidimetry
Polymorphonuclear leukocytes
Nephlometry measures light transmitted
Feedback
through a solution, and turbidimetry measures
light scattered in a solution In addition to T lymphocytes, macrophages,
peripheral blood monocytes, and cells in the
lymph nodes, skin, and other organs also
express measurable amounts of CD4 and can be
infected by HIV-1.
Untitled Section

2 of 2 points

A bacterial protein used to bind human

immunoglobulins is:*

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HAV antibody, IgA type

Escherichia coli protein C

Staphylococcal protein A

HAV antibody, IgG type

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Protein A, found in the cell walls of

Staphylococcus aureus bacteria, has high
affinity for the Fc region of IgG and can be used
to bind IgG in some laboratory assays.

Untitled Section

2 of 2 points

Which of the following is used to detect allergen

specific IgE?*

2/2

RIST

RAST

IEP

CRP

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RIST - measures TOTAL IgE

RAST - measures SPECIFIC IgE