Deck 10: Immunodiagnosis of Infectious Diseases

Question 1

A monoclonal antibody is:

A) An antibody that is derived from one cell, exposed to many epitopes
B) An antibody that is derived from many cells, exposed to one epitope
C) An antibody that is derived from one cell and exposed to no epitopes
D) An antibody that is derived from one cell initially, which has been exposed to one epitope

Answer 1

D
This antibody is derived from one cell initially,which has been exposed to one epitope.This cell then divides and produces an antibody specific to this one epitope.Monoclonal antibodies are rarely found in nature and are usually associated with some type of abnormal immune disease process.

Question 2

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

Answer 2

B
A positive result for IgM antibody is considered indicative of a primary,current,or very recent infection.John just became ill,so this is a primary response to a virus.Therefore the antibody produced is IgM.

Question 3

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

Answer 3

A
A subsequent exposure to the same antigen elicits a secondary or anamnestic response,characterized by a rapid increase in IgG antibody associated with higher levels,a prolonged elevation,and a more gradual decline.

Question 4

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 5

Mary went out to eat shellfish last week and is 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 6

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) Immunosuppressive

Question 7

Antibodies for many antigens can be passively acquired in:

A) Vaccinations
B) Flu shots
C) Intravenous immunoglobulin therapy
D) All of the above

Question 8

What tests are performed on newborns to detect congenital infections?

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

Question 9

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 10

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 11

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

Question 12

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

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

Question 13

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 14

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.

Question 15

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 labeled antigen, and a sandwich reaction occurs.
C) Antibodies and antigens combine then precipitate out of solution to the bottom of the tube.
D) The antigen-antibody reaction forms a macroscopically visible clump that remains in solution.

Question 16

Avidity means the antibodies have:

A) Strong binding kinetics to specific antigens
B) Weak binding kinetics to specific antigens
C) Strong binding kinetics to specific antibodies
D) Weak binding kinetics to specific antibodies

Question 17

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 18

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 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

Heterophile antibodies are:

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

Question 21

Enzyme immunoassay (EIA)differs from immunofluorescent tests by:

A) Using a different fluorescent label
B) Using a enzymes and a chromogenic substrate
C) Being valid for direct testing only
D) All of the above

Question 22

Confirmatory tests for syphilis include all the following EXCEPT:

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

Question 23

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

A) One enzyme conjugated anti-immune 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 24

All of the following controls must accompany the patient specimens in a latex agglutination EXCEPT:

A) Positive antigen control
B) Negative antigen control
C) Latex suspension control
D) Positive antibody control

Question 25

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 26

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

A) Deafness
B) Blindness
C) Cataracts
D) Congenital heart disease

Question 27

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 28

Streptozyme detects all of the following EXCEPT:

A) Streptokinase
B) Hyaluronidase
C) Streptolysin-O
D) Hippurate hydrolysis

Question 29

What is the difference between dot blots and Western blots?

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 30

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 31

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 32

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 33

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 34

A direct fluorescent antibody (DFA)test involves:

A) Antigen-specific labeled antibody
B) Antibody-specific labeled antigen
C) Bioluminescent label
D) None of the above

Question 35

Indirect agglutination is also referred to as:

A) Passive agglutination
B) Incomplete agglutination
C) Active agglutination
D) Flocculation

Question 36

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) Subjectivity in reading endpoints

Question 37

Prozone occurs:

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

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

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

A) Misshapen limbs
B) Congenital heart defects
C) Liver problems
D) Microencephalopathy

Question 40

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

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

Question 41

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 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

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

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

Question 44

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 45

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 46

How is hepatitis B transmitted?

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

Question 47

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

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

Question 48

Which organism is DFA used to detect,despite the test having a low sensitivity (25% to 75%)?

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

Question 49

What is the earliest serologic marker detected in hepatitis B?

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

Question 50

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

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

Question 51

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

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

Question 52

Which hepatitis virus 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 53

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

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

Question 54

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

A) Norwalk
B) Rotavirus
C) Enteric adenoviruses
D) Cytomegalovirus (CMV)

Question 55

All of the following are hepatitis antibodies EXCEPT:

A) EBNA
B) HBsAb
C) HBcAb
D) HBeAb

Question 56

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)