Deck 10: Immunodiagnosis of Infectious Diseases

Question 1

Serologic tests can help epidemiologists:

A)determine if people in a particular area are immune to an infectious agent.
B)identify people that need to get immunizations.
C)identify children that need to get immunizations.
D)determine how widespread an infectious agent is in a given area.

Answer 1

D
Serologic tests for a specific infectious agent or a battery of agents may be performed to determine the percentage of individuals previously exposed or infected with the agent(s) in a geographic area.This information provides epidemiologists and public health officials with information about how widespread an infectious agent is in a given area.

Question 2

In precipitation assays, what is the precipitate made out of?

A)Complement and protein complex
B)Antibody and protein complex
C)Antigen and antibody complex
D)Antigen and protein complex

Answer 2

C
The precipitation reaction is found in assays involving the diffusion of soluble antigen and antibody.At a critical point, when the concentrations are optimal, a visible precipitate forms, which is composed of an insoluble complex of antigens and antibodies.

Question 3

When the antigen-binding sites on the antibody molecule react with specific epitopes and not with other antigens containing different epitopes, this is antibody molecule is displaying:

A)high sensitivity.
B)high specificity.
C)low specificity.
D)low sensitivity.

Answer 3

B
Most antigen-antibody reactions show high specificity; that is, the antigen-binding sites on the antibody molecule react with specific epitopes and not with other antigens containing different epitopes.

Question 4

A false-negative test may be caused by all the following immune system-mediated reasons except:

A)allergic reaction.
B)no immune response.
C)immunodeficiency disease.
D)immunosuppression.

Question 5

Antibodies for many antigens can be passively acquired in:

A)vaccinations.
B)flu shots.
C)intravenous immunoglobulin therapy.
D)all of the above.

Question 6

Mary went out to eat shellfish last week and is now beginning to feel lethargic.Her urine is tea-colored, and she generally feels bad all over.She recognizes these symptoms and thinks she may have hepatitis A because she got hepatitis last year when she vacationed at the beach.If a physician were to perform a test for hepatitis A antibodies, what class of antibodies would the physician find?

A)IgM
B)IgE
C)IgG
D)IgD

Question 7

What is the principle of the flocculation test?

A)The antigen is incorporated into the agar and the test wells hold the antibody.The antibody and antigen combine at a specific concentration and produce a zone of equivalence.
B)Antibodies are mixed with a labeled antigen, and a sandwich reaction occurs.
C)Antibodies and antigens combine then precipitate out of a solution to the bottom of the tube.
D)The antigen-antibody reaction forms a macroscopically visible clump that remains in solution.

Question 8

If a baby were exposed to hepatitis A in utero, what type of antibodies would be produced?

A)IgD
B)IgE
C)IgG
D)IgM

Question 9

A false-negative serologic test is defined as a:

A)positive result for someone who is not infected.
B)negative result for someone who does not have the disease.
C)positive result for someone who does have the disease.
D)negative result for a patient who really is infected.

Question 10

How can one determine if a person has had a previous illness with an organism?

A)Perform acute and convalescent IgM levels.
B)Perform acute and convalescent IgG levels.
C)Perform an IgM level 1 week after the symptoms start.
D)Perform an IgG level 1 week after the symptoms start.

Question 11

John goes to his physician complaining of a high fever (38.2° C [102° F]), muscle aches, cough, and a headache.These symptoms came on suddenly, and his physician thinks John may have the flu.What kind of antibody is his body producing against the virus?

A)IgG
B)IgM
C)IgE
D)IgD

Question 12

When a person is exposed to an antigen for a second time, what type of response is mounted?

A)Anamnestic
B)Tertiary
C)Full blown
D)Allergic

Question 13

A monoclonal antibody is an antibody that is derived from:

A)one cell and exposed to many epitopes.
B)many cells and exposed to one epitope.
C)one cell and exposed to no epitopes.
D)one cell initially, which has been exposed to one epitope.

Question 14

A significant rise in IgG detected during the convalescent phase is diagnostic for infection and is called:

A)serologic adaptation.
B)convalescence.
C)seroconversion.
D)acute phase reactant.

Question 15

Heterophile antibodies are antibodies:

A)produced in response to one antigen.
B)that must be cleared through the thymus before going into circulation.
C)produced in response to one molecule that also react against an antigen from another species.
D)produced by T cells.

Question 16

What is the principle of direct antigen testing?

A)A clinical specimen is mixed with an antigen, then a labeled antibody is added.If the antigen is present, a complex will form.
B)It is a process by which microbial antigens are identified in patient specimens by combining specifically with antibody molecules to form stable complexes.
C)A fluorescent antigen is added to a specimen, then an antibody to form sandwich complexes.
D)Labeled antigen is added to a specimen, and the specimen is read for fluorescence.

Question 17

Avidity means the antibodies have _____ binding kinetics to specific _____.

A)strong; antigens
B)weak; antigens
C)strong; antibodies
D)weak; antibodies

Question 18

What can cause a false-positive IgM serologic test?

A)The presence of IgG antibodies
B)The presence of rheumatoid factors
C)The presence of Rh factor
D)The presence of cytomegalovirus (CMV) antibodies

Question 19

What is one of the most popular methods for physical removal of IgG?

A)Miniature ion-exchange chromatography columns
B)Thin-layer chromatography
C)High-performance liquid chromatography (HPLC)
D)Mass spectroscopy

Question 20

What tests are performed on newborns to detect congenital infections?

A)TORCH
B)TWAR
C)CMV
D)HIV

Question 21

The difference between dot blots and Western blots is that in dot blot testing:

A)proteins are blotted to specific areas.
B)proteins are purified and directly blotted to specific locations on the solid surface.
C)DNA is purified and directly blotted to specific locations on the solid surface.
D)RNA is purified and directly blotted to specific locations on the solid surface.

Question 22

Prozone occurs:

A)when the relative concentration of an antibody exceeds the concentration of an antigen.
B)when the relative concentration of an antigen exceeds the concentration of an antigen.
C)when there are interfering substances in the specimen.
D)in the equivalence zone.

Question 23

What are the benefits of using membranes to perform enzyme immunoassay (EIA) reactions?

A)They improve specificity and signal strength.
B)They enhance speed and signal strength.
C)They enhance speed and sensitivity.
D)They improve specificity and sensitivity.

Question 24

Enzyme immunoassay (EIA) differs from immunofluorescent tests by:

A)using a different fluorescent label.
B)using enzymes and a chromogenic substrate.
C)being valid for direct testing only.
D)all of the above.

Question 25

Confirmatory tests for syphilis include all the following except:

A)FTA-ABS.
B)TP-PA.
C)RPR.
D)MHA-TP.

Question 26

What is ASO used for?

A)To demonstrate serologic response to streptococcal antigen
B)To determine if a strep has been lysogenized
C)To determine if a strep produces a hemolysin
D)To demonstrate serologic response to Streptococcus pyogenes

Question 27

What is used as the indicator in a complement fixation (CF) test?

A)Latex particles
B)Horse red blood cells
C)Rabbit red blood cells
D)Sheep red blood cells

Question 28

All of the following are congenital defects produced by rubella except:

A)deafness.
B)blindness.
C)cataracts.
D)congenital heart disease.

Question 29

All of the following controls must accompany the patient specimens in a latex agglutination test for antigen detection except _____ control.

A)positive antigen
B)negative antigen
C)latex suspension
D)positive antibody

Question 30

Indirect agglutination is also referred to as:

A)passive agglutination.
B)incomplete agglutination.
C)active agglutination.
D)flocculation.

Question 31

What is the advantage of using an indirect sandwich assay for EIA?

A)One enzyme conjugated antiimmune antibody can be used for several tests.
B)It is much more specific than direct sandwich EIA.
C)It is much more sensitive than direct sandwich EIA.
D)The lower detection limit is superior to any other EIA test.

Question 32

What is one of the biggest uses for Western blot tests in the laboratory today?

A)Confirming antibodies to HIV
B)Confirming antibodies to cytomegalovirus (CMV)
C)Confirming antibodies to rubella
D)DNA sequencing from herpes

Question 33

Streptozyme detects all of the following except:

A)streptokinase.
B)hyaluronidase.
C)streptolysin-O.
D)hippurate hydrolysis.

Question 34

What is the name of the test used to detect rickettsial agents?

A)Levy-Jennings
B)Mueller-Hinton
C)Weil-Felix
D)Watson-Crick

Question 35

The advantages of latex agglutination include all the following except:

A)availability of good quality reagents in complete kit form.
B)good sensitivity.
C)ease of performance.
D)cost of reagents.

Question 36

What test has its results reported as the relative amount of a signal generated by the patient's serum when compared with that of a known weakly positive serum?

A)Enzyme immunoassay (EIA)
B)Enzyme-linked immunosorbent assay (ELISA)
C)Radioimmunoassay (RIA)
D)Solid phase immunobead assay (SPIA)

Question 37

Infection with cytomegalovirus (CMV) in nonimmune pregnant women can cause:

A)misshapen limbs.
B)congenital heart defects.
C)liver problems.
D)microencephalopathy.

Question 38

What test principle uses microbial antigens that are attached to erythrocytes after chemical treatment of the cells that promotes cross-linking of the antigens?

A)Indirect hemagglutination (IHA)
B)Enzyme immunoassay (EIA)
C)Complement fixation (CF)
D)Latex agglutination (LA)

Question 39

What test is used to diagnose an Epstein-Barr virus (EBV) infection?

A)ASO
B)EBV antibody
C)Heterophile antibody
D)Cold agglutinin

Question 40

A direct fluorescent antibody (DFA) test involves:

A)an antigen-specific labeled antibody.
B)an antibody-specific labeled antigen.
C)a bioluminescent label.
D)none of the above.

Question 41

How is hepatitis B transmitted?

A)Contaminated food and water
B)Blood and body fluids
C)Respiratory droplets
D)Airborne

Question 42

What two methods are used to diagnose histoplasmosis and coccidioidomycosis?

A)Complement fixation and immunodiffusion
B)Enzyme immunoassay (EIA) and immunodiffusion
C)Complement fixation and hemagglutination inhibition (HAI)
D)Agglutination and precipitation

Question 43

All of the following are hepatitis antibodies except:

A)EBNA.
B)HBsAg.
C)HBcAg.
D)HBeAg.

Question 44

Latex agglutination kits are currently available for all the following bacterial antigens except:

A)Cryptococcus neoformans.
B)Neisseria meningitidis.
C)Haemophilus influenzae.
D)Streptococcus pneumoniae.

Question 45

Which hepatitis virus commonly leads to chronic hepatitis and cirrhosis, often requiring a liver transplant, and causes a high risk for development of liver cancer?

A)Hepatitis A
B)Hepatitis D
C)Hepatitis C
D)Hepatitis E

Question 46

What is one of the most widely used applications of the direct antigen test?

A)HIV in saliva
B)Group A strep in throat swabs
C)Epstein-Barr virus (EBV) in urine
D)Cytomegalovirus (CMV) in hair follicles

Question 47

What patients are highly susceptible to cytomegalovirus (CMV) infections?

A)Immunosuppressed
B)Immunocompetent
C)Males
D)Females

Question 48

All of the following are identifiable viral agents of gastroenteritis except:

A)Norwalk.
B)rotavirus.
C)enteric adenoviruses.
D)cytomegalovirus (CMV).

Question 49

For which organism is DFA used for detection, despite the test having a low sensitivity (25% to 75%)?

A)Neisseria
B)Streptococcus
C)Legionella
D)Klebsiella

Question 50

All of the following are important pulmonary pathogens in transplant, cancer, and AIDS patients except:

A)Cryptococcus.
B)Group A Streptococcus.
C)Pneumocystis.
D)Cytomegalovirus (CMV).

Question 51

Which test is a confirmatory test of enzyme-linked immunosorbent assay (ELISA) HIV?

A)Enzyme immunoassay (EIA)
B)Northern blot
C)Southern blot
D)Western blot

Question 52

All of the following are antigens present in a hepatitis B infection except:

A)HBsAg.
B)HBcAg.
C)HBeAg.
D)VCNA.

Question 53

How does Clostridium difficile produce pseudomembranous colitis and antibiotic-associated diarrhea?

A)Endotoxin
B)Hyaluronidase
C)Toxin A and toxin B (exotoxins)
D)Protease

Question 54

Which organism can cause hospitalization in young children and is detected using fluorescent antibodies?

A)Bordetella
B)Klebsiella
C)Streptococcus
D)Respiratory syncytial virus (RSV)

Question 55

What is the earliest serologic marker detected in hepatitis B?

A)HAV
B)HBsAg
C)HBcAg
D)HBeAg

Question 56

Which hepatitis virus is spread by the fecal/oral route?

A)Hepatitis B
B)Hepatitis A
C)Hepatitis C
D)Hepatitis D