Deck 9: Immunochemical Methods Used for Organism Detection

Question 1

A positive latex agglutination test was observed in a sample containing Cryptococcus neoformans.The specimen of choice to identify this pathogen is:

A) urine.
B) blood.
C) stool.
D) cerebrospinal fluid (CSF).

Answer 1

D
C.neoformans is best identified in the CSF or serum with latex agglutination tests.Whole blood, stool, and urine are not appropriate specimens for identification purposes.

Question 2

The precipitin test that involves antigen and antibody diffusing toward each other, producing a visible precipitin band at the point at which they meet, is referred to as:

A) double immunodiffusion.
B) counterimmunoelectrophoresis.
C) particle agglutination.
D) enzyme immunoassay.

Answer 2

A
Double immunodiffusion is a test that involves an antigen and antibody diffusing toward each other to produce a precipitin band at the meeting point.

Question 3

The difference between latex agglutination and coagglutination is:

A) the type of particle used to carry the antibody.
B) the type of target organism involved.
C) that coagglutination is less specific but more sensitive.
D) that coagglutination, not latex agglutination, can be used for direct antigen detection.

Answer 3

A
Latex agglutination uses latex particles, whereas coagglutination uses Staphylococcus aureus cells.

Question 4

Monoclonal antibodies are those that:

A) react with many different types of antigens.
B) react with many species of bacteria within the same genus.
C) are produced by the offspring of a single hybrid cell.
D) can be produced from many different species of host organisms.

Question 5

A test procedure that applies a specific fluorescent dye-antibody complex to a slide to which the patient specimen has been applied is referred to as a(n):

A) solid-phase enzyme immunoassay.
B) direct fluorescent antibody test.
C) indirect fluorescent antibody test.
D) radioimmunoassay.

Question 6

A modification of the Ouchterlony method that speeds up the migration of an antigen and antibody by applying an electrical current is referred to as:

A) double immunodiffusion.
B) counterimmunoelectrophoresis.
C) particle agglutination.
D) enzyme immunoassay.

Question 7

Polyclonal antibodies are those that:

A) react with many different types of antigens.
B) react with many species of bacteria within the same genus.
C) react with many different antigens of one specific organism.
D) can be produced from many different species of host organisms.

Question 8

The major advantage of immunofluorescent microscopy assays is that:

A) extensive training is not necessary.
B) it serves as an excellent way to preserve the reaction for referral and archiving.
C) visual assessment of the adequacy of a specimen is possible.
D) fluorescent microscopes are easily accessible to most laboratories.

Question 9

A sample suspected of containing Legionella pneumophila is treated with the dye fluorescein isothiocyanate (FITC); however, the sample fluoresced a bright apple-green colony after it was processed.Which of the following statements explains this discrepancy?

A) A technical error may have occurred.
B) The fluorescent bulb may have malfunctioned.
C) The results are accurate; no discrepancy is found.
D) A postanalytical error is to blame.

Question 10

The immunochemical test that involves an antigen present in a specimen binding to the combining sites of the antibody exposed on the surfaces of latex beads is referred to as:

A) double immunodiffusion.
B) counterimmunoelectrophoresis.
C) particle agglutination.
D) enzyme immunoassay.