Deck 17: Procedures for Identifying Pathogens and Diagnosing Infections

Question 1

Which test is the confirming test for people who initially tested antibody-positive in the screening ELISA test?

A)Ouchterlony double diffusion
B)Western blot
C)immunelectrophoresis
D)radioimmunoassay (RIA)
E)the Quellung test

Answer 1

B

Question 2

The physician orders an antistreptolysin O (ASO) titer test to check for rheumatic fever. A patient serum sample is exposed to known suspensions of streptolysin and then allowed to incubate with RBCs? If the patient does have rheumatic fever, what will happen?

A)Not enough information is provided to speculate.
B)The red blood cells will lyse.
C)The red blood cells will agglutinate only.
D)The red blood cells will not lyse.
E)None of the above.
F)The red blood cells will fluoresce.

Answer 2

D

Question 3

When serum proteins are separated by electrophoresis and then antibodies specific for the serum proteins are placed in a parallel trough in order to form reaction arcs for each protein, the test is called:

A)Ouchterlony double diffusion.
B)Western blot.
C)immunelectrophoresis.
D)radioimmunoassay (RIA).
E)the Quellung test.

Answer 3

C

Question 4

Which technique used to diagnose a disease is also called the double diffusion method?

A)Ouchterlony test
B)VDRL test
C)immunoelectrophoresis
D)Western blot
E)ELISA

Question 5

Whole antigens are detected in which type of test?

A)cross-reactions
B)agglutination
C)precipitation
D)specificity
E)sensitivity

Question 6

Precipitation tests involve all of the following, except:

A)they rely on formation of visible clumps for detection.
B)they include the VDRL test for syphilis.
C)they are often performed in agar gels.
D)they can be done in a test tube by carefully adding antiserum over antigen solution.
E)a cloudy or opaque zone developing where antigen and antibody react

Question 7

Soluble antigens are detected in which type of test?

A)cross-reactions
B)agglutination
C)precipitation
D)specificity
E)sensitivity

Question 8

Which of the following methods is categorized as a direct test in order to analyze a specimen?

A)Catalase test
B)Gram stain
C)Phage typing
D)Antimicrobic sensitivity
E)Production of gas

Question 9

Serotyping of the pneumococcus based on capsular polysaccharide is performed in:

A)Ouchterlony double diffusion.
B)Western blot.
C)immunelectrophoresis.
D)radioimmunoassay (RIA).
E)the Quellung test.

Question 10

All of the following are methods to diagnose viral infections, except:

A)detection of viral nucleic acid using specific probes.
B)Western blot.
C)cells taken from patient are examined for evidence of viral infection.
D)signs and symptoms.
E)the light microscope.

Question 11

Which test uses radioactive isotopes to label antibodies or antigens in order to detect minute amounts of corresponding antigen or antibody?

A)Ouchterlony double diffusion
B)Western blot
C)immunelectrophoresis
D)radioimmunoassay (RIA)
E)the Quellung test

Question 12

The property of a test to detect even small amounts of antibodies or antigens that are test targets is:

A)cross-reactions.
B)agglutination.
C)precipitation.
D)specificity.
E)sensitivity.

Question 13

Which of the following is not a biochemical test used to identify a pathogen?

A)Acid-fast reaction
B)Hydrolysis of gelatin
C)Coagulase production
D)Oxygen requirements
E)Carbohydrate fermentation

Question 14

Which of the following choices are true about the dyes fluorescein and rhodamine?

A)They can be used to label antibodies in immunofluorescence tests.
B)They emit visible light in response to ultraviolet radiation.
C)They are observed in the fluorescent microscope.
D)They re used to identify pathogens of chlamydiosis, Legionnaires' disease, and others.
E)All of the choices are true.

Question 15

Affixing antigen to an inert particle such as a latex bead is sometimes used in which type of test?

A)cross-reactions
B)agglutination
C)precipitation
D)specificity
E)sensitivity

Question 16

The property of a test to detect only a certain antibody or antigen, and not to react with any others, is:

A)cross-reactions.
B)agglutination.
C)precipitation.
D)specificity.
E)sensitivity.

Question 17

Which of the following is incorrect regarding the complement fixation test?

A)First antigen and antibody are allowed to react.
B)Purified complement proteins are added to the antigen-antibody tube.
C)Sheep red blood cells are added to the antigen-antibody-complement mixture.
D)Hemolysis of the sheep red blood cells occurs in a positive test result.
E)None of the choices are correct.

Question 18

Which of the following choices are true about viral hemagglutination testing?

A)It uses a red blood cell that naturally reacts with viral antigens.
B)It analyzes patient serum for specific antibodies to a virus.
C)It has hemagglutination if the patient serum lacks virus specific antibodies.
D)it is used to diagnosis viral diseases such as rubella and mononucleosis.
E)All of the choices are true.

Question 19

A serum titer involves:

A)serially diluting a serum sample.
B)determining the lowest dilution of serum that produces a visible reaction.
C)determining the highest dilution of antigen that produces a visible reaction.
D)the Western blot method.
E)None of the above mentioned choices.

Question 20

Which of the following is involved in the in vitro diagnostic testing of serum?

A)mycology
B)hematology
C)serology
D)histology
E)virology

Question 21

A rising antibody titer a few days apart indicates:

A)The patient had a past case of the disease.
B)The patient has a current infection.
C)Nothing, people always have antibodies in their serum.
D)All of the above mentioned choices are possible.
E)None of the above mentioned choices are possible.

Question 22

Which test is used to measure the IgE present in allergic patients?

A)fluorescent antibody tests
B)Rapid Plasma Reagin (RPR) test
C)Weil-Felix reaction
D)RIST
E)ELISA

Question 23

The more a sample can be diluted and yet still react with antigen, the ______ the concentration of antibodies in that sample and the _______ is its titer.

A)lower, lower
B)higher, lower
C)lower, higher
D)higher, higher

Question 24

The Widal test is used for diagnosing salmonellosis.

Question 25

Test systems involving which of the following has greatly improved the specificity of immunological tests?

A)monoclonal antibodies
B)electronics
C)enzymes
D)radioactivity
E)All of the choices are correct.

Question 26

When antigen-antibody reactions are used to read a _____, they determine the quantity of antibodies in the serum.

Question 27

Mary had an accidental needlestick one night during her shift as an emergency medical technician.Initially, she tested positive for HIV by the ELISA test.Which test would be done next to confirm an HIV infection?

A)immunoelectrophoresis
B)Ouchterlony
C)complement fixation
D)Western blot
E)radioimmunoassay

Question 28

In direct antigen testing, the reaction is generally seen with the:

A)electron microscope.
B)naked eye.
C)light microscope.
D)API 20E miniature identification system.
E)PCR reaction.

Question 29

Sputum is obtained by:

A)swabbing the mouth to sample saliva.
B)a clean catch urine sample.
C)the patient coughing up mucus from the lower respiratory system.
D)a spinal tap above the chest.
E)a throat swab.

Question 30

The indirect ELISA test detects ______ in a patient's blood.

A)antigen
B)antibody
C)microorganisms
D)IgE only
E)complement

Question 31

Broad general characteristics of bacteria on flowcharts can be misleading for a diagnosis of disease.

Question 32

Maggie was told she has a positive titer to measles.Which of the following could explain this?

A)She was vaccinated against measles.
B)She had measles sometime in her life.
C)She has measles now.
D)The test was a false positive.
E)All of the choices are correct.

Question 33

The tuberculin test is an example of an in vivo serological test.

Question 34

Some diseases are diagnosed without the need to identify microbes from a patient specimen.

Question 35

ELISA tests use a fluorescent dye as a label to trace antigen-antibody reactions.

Question 36

All of the following are routine biochemical tests to aid in identifying a species, except:

A)motility.
B)carbohydrate fermentation.
C)catalase test.
D)oxidase test.
E)coagulase test.

Question 37

When antibodies or other substances in serum cross-react with the test reagents, a false positive result can occur.

Question 38

Serological testing always involves reactions between specific antibody and antigen.

Question 39

Serological tests should have low sensitivity and specificity.

Question 40

All of the following are correct about the indirect ELISA, except:

A)it can detect antibodies in a serum sample.
B)it is the common screening test for antibodies to Helicobacter.
C)color development indicates that antibody was not present in the patient's serum.
D)it is the common screening test for antibodies to Hepatitis A.
E)a known antigen is adsorbed to the surface of a well.

Question 41

In a __________, antigens or antibodies are labeled with radioactive isotopes and traced.

Question 42

Identify, describe, and discuss the objectives of the three main categories of identifying infectious agents using specific examples.

Question 43

Flowcharts that offer two choices at each identifying level are called ___ keys.

Question 44

Why do many physicians feel that stool cultures are not necessary, except in certain circumstances when diagnosing GI tract infections?

Question 45

In indirect fluorescent testing, fluorescent _____ are used to react with the Fc region of another, specific, serum antibody.

Question 46

Horseradish peroxidase and alkaline phosphatase are enzymes used in _____ tests.

Question 47

In lab, a student observes some dull, wrinkled brown colonies growing on their agar.They gram stain the sample and observe single bacilli.Their blood agar does not reveal any hemolysis while their MSA has growth and fermentation.Using the following table and the given observations, determine which microorganism this would most likely be.

A)E. coli
B)Pseudomonas aeruginosa
C)B. subtilis
D)B. cereus

Question 48

In _________ tests, antibody cross-links whole-cell antigens, forming complexes that settle out and form visible clumps in the test chamber.

Question 49

Describe the indirect ELISA test that is used as a screening test for HIV (AIDS) and include the following: a) sequence of procedures, b) reagents used, and c) detection and interpretation of a positive test.

Question 50

Describe three possible sampling sites and methods of collection for clinical laboratories.

Question 51

Compare and contrast agglutination and precipitation reactions, and include a description of one test for each type of reaction.

Question 52

A simple method to detect _____ cells involves mixing them with untreated sheep red blood cells that will bind and form rosettes.

Question 53

When collecting __________, a "clean catch" method is often used.