Question 1

The immunochemical test that involves the agglutination of an artificial carrier particle with the antigen bound to its surface and an antibody present in a specimen is referred to as:

Accepted Answer

Methods that use particle agglutination involve an antibody that is present in a specimen that binds to the antigen that is exposed on the surfaces of particles,such as latex beads or other carrier particles.

Question 2

A positive test was observed on a serum sample that resulted in the formation of a fine precipitate on a reaction card.The most likely organism serologically identified is:

Accepted Answer

A fine precipitate is formed with flocculation tests.The rapid plasma reagin (RPR)and Venereal Disease Research Laboratory (VDRL)are two types of flocculation assays that test for T.pallidum,the causative agent of syphilis.

Question 3

A Western blot assay was performed,and bands were observed at p24,p41,and gp120/160 (kilodaltons).The organism can be identified as:

Accepted Answer

In the HIV Western blot test,a positive blot has any two of the following bands: p24,p41,and gp120/160.

Question 4

A patient was suspected of having a rickettsial infection after hiking in the Rocky Mountains.A Weil-Felix test was performed,which resulted in no agglutination observed.Which one of the following statements explains this discrepancy?

Accepted Answer

The Weil-Felix test is an older method and is not as sensitive as some of the newer tests;therefore,infections should be retested to ensure an accurate result.

Question 5

The difference between latex agglutination and hemagglutination is:

Accepted Answer

Latex agglutination uses latex particles,whereas hemagglutination uses red blood cells.

Question 6

A pregnant woman had contact with her nephew who was just diagnosed with a rubella infection.Acute and convalescent samples were taken,which resulted in an acute titer of 1:16 and a convalescent titer of 1:32.Which one of the following comments explains the risk to the fetus?

Accepted Answer

No fourfold rise is present in titer (two doubling dilutions);in addition,the pregnant woman is immune with a titer of greater than 1:8.Therefore,the risk to the developing fetus is low since the pregnant woman has enough antibodies to cross the placenta and protect the fetus.

Question 7

Specific proteins produced by cells of the immune system in response to the presence of foreign molecules that circulate in the serum and are present in secretions such as saliva are called:

Accepted Answer

Produced by B lymphocytes in response to the presence of foreign molecules,immunoglobulins (or antibodies)are present in serum and in secretions such as saliva and are the central molecule of the immune response.

Quiz 9: Overview of Immunochemical Methods Used for Organism Detection