Question 1

Describe the technique of measuring acute and convalescent titers in an infection and how the titers can be used to make a diagnosis.

Accepted Answer

The answer of Describe the technique of measuring acute and...

Question 2

Which technique below describes Ouchterlony double diffusion?

Accepted Answer

A) Antibodies are added to liquid agarose, and the agarose is allowed to harden. Holes are cut in agarose, and specimens are placed in the holes. The specimens diffuse out of their wells, forming precipitin rings. 
B) Antibodies are added to liquid agarose, and the agarose is allowed to harden. Holes are cut in agarose, and specimens are placed in the holes. The agarose is placed in an electrical field, and the specimens migrate out of their wells, forming precipitin lines. 
C) Holes are cut in agarose. Antibodies are placed in one well, and a specimen is placed in the other well. The agarose is placed in an electrical field, and the antibodies and specimen migrate out of their wells, meeting in the middle, forming a precipitin line. 
D) Holes are cut in agarose. Antibodies are placed in one well, and a specimen is placed in the other well. The antibodies and specimen diffuse out of their wells, meeting in the middle, forming a precipitin line.

Question 3

An important agent of childhood gastroenteritis that can be identified by extracting viral antigen from stool samples and reacting it with corresponding antibody is

Accepted Answer

A) rotavirus. 
B) norovirus. 
C) coronavirus. 
D) adenovirus. 
E) calcivirus.

Question 4

What does the formula below calculate?

Where true positive results are patients with a disease who test positive and false negatives are patie with a disease who test negative

Accepted Answer

A) Clinical sensitivity 
B) Clinical specificity 
C) Accuracy 
D) Precision

Question 5

How can soluble antigens with multiple epitopes be mixed with antibodies and have visible agglutination occur?

Accepted Answer

A) Attach the antibodies to killed Staphylococcus aureus cells. 
B) Attach the antibodies to liposomes. 
C) Attach the antibodies to latex particles. 
D) All of the above.

Question 6

By law, laboratories may not use "home- brew" or non- FDA approved tests.

Accepted Answer

A) True 
 B)False

Question 7

Which characteristic(s)below do herpes viruses share?

Accepted Answer

A) Generally only cause clinical symptoms in immunocompromised patients. 
B) Active infections that become latent, potentially reactivating many years later. 
C) Virtually impossible to grow in artificial cell culture. 
D) Poor antibody response to infection and generally insensitive serologic testing. 
E) All of the above.

Question 8

A patient is covered by a rash over most of his body, including the palms of the hands and soles of the feet. He also has lymphadenopathy, fatigue, and fever. His RPR is positive with a titer of 1:1024, and his FTA- Abs is positive. This description is most consistent with

Accepted Answer

A) primary syphilis. 
B) latent syphilis. 
C) tertiary syphilis. 
D) biological false positive test for syphilis. 
E) secondary syphilis.

Question 9

Which hepatitis virus(s)below is (are)transmitted by the fecal/oral route?

Accepted Answer

A) Hepatitis D (delta agent)virus 
B) Hepatitis A virus 
C) Hepatitis B virus 
D) Hepatitis C virus 
E) All of the above

Question 10

Rapid immunological assays for Group A Streptococcus pyogenes antigen have a sensitivity of about 60% to 80% and a specificity of about 90% to 95% in pharyngitis infections. Given these data, which strategy below is optimal?

Accepted Answer

A) Do preliminary screening with a throat culture and follow up negative results with a rapid antigen test. 
B) Do preliminary screening with a rapid antigen test and follow up negative results with a throat culture. 
C) Do preliminary screening with a rapid antigen test and follow up positive results with a throat culture. 
D) Do preliminary screening with a throat culture and follow up positive results with a rapid antigen test. 
E) Simultaneously test all specimens with both rapid antigen screening and culture.

Question 11

A positive test for hepatitis C antibody can be confirmed by ________or ________.

Accepted Answer

The answer of A positive test for hepatitis C antibody...

Question 12

Which of the following non- treponemal tests must be read using a microscope?

Accepted Answer

A) Toluidine red unheated serum test (TRUST) 
B) Venereal Disease Research Laboratory (VDRL) 
C) RST- reagin screen 
D) Rapid plasma reagin (RPR) 
E) All of the above

Question 13

Adults tend to have a poorer heterophile antibody response in infectious mononucleosis than children.

Accepted Answer

A) True 
 B)False

Question 14

What advantage does countercurrent immunoelectrophoresis have over Ouchterlony double diffusion?

Accepted Answer

A) It requires a smaller specimen volume. 
B) It is faster. 
C) It requires less instrumentation. 
D) Complement does not interfere with the procedure.

Question 15

A chronic carrier of hepatitis B virus typically fails to develop the ________antibody and the________ antibody.

Accepted Answer

The answer of A chronic carrier of hepatitis B virus...

Question 16

In general, rapid immunoassays for Legionella pneumophilia have the highest sensitivities and specificities when the specimen tested is

Accepted Answer

A) serum or plasma. 
B) whole blood. 
C) urine. 
D) a deep cough sputum. 
E) a nasopharyngeal swab.

Question 17

In the normal course of a hepatitis B virus infection, what is the order of appearance of the following markers in serum? 1. Hepatitis B surface antigen
2) Hepatitis B early antigen
3) Anti- hepatitis B surface antigen
4) Anti- hepatitis B early antigen
5) Anti- hepatitis B core antigen

Accepted Answer

A) 1, 2, 3, 4, 5 
B) 1, 2, 5, 4, 3 
C) 2, 1, 4, 3, 5 
D) 2, 1, 3, 4, 5

Question 18

A positive test for the presence of antibodies in a complement fixation test is

Accepted Answer

A) lysis of red blood cells. 
B) no lysis of red blood cells. 
C) precipitation of antigen/antibody complexes. 
D) no precipitation of antigen/antibody complexes.

Question 19

An advantage of using Staphylococcus aureus cells for coagglutination instead of liposomes is that a colored dye can be incorporated into the Staphylococcus aureus enhancing visualization of the agglutination.

Accepted Answer

A) True 
 B)False

Question 20

Explain the properties of the Cowan 1 strain of Staphylococcus aureus that allow it to be a passive carrier of antibody in coagglutination procedures and how these properties contribute to an increased chance of false positive tests in some specimens.

Accepted Answer

The answer of Explain the properties of the Cowan 1...

Exam 7: Immunologic Detection of Infectious Diseases

Describe the technique of measuring acute and convalescent titers in an infection and how the titers can be used to make a diagnosis.

Which technique below describes Ouchterlony double diffusion?

An important agent of childhood gastroenteritis that can be identified by extracting viral antigen from stool samples and reacting it with corresponding antibody is

What does the formula below calculate? Where true positive results are patients with a disease who test positive and false negatives are patie with a disease who test negative

How can soluble antigens with multiple epitopes be mixed with antibodies and have visible agglutination occur?

By law, laboratories may not use "home- brew" or non- FDA approved tests.

Which characteristic(s) below do herpes viruses share?

A patient is covered by a rash over most of his body, including the palms of the hands and soles of the feet. He also has lymphadenopathy, fatigue, and fever. His RPR is positive with a titer of 1:1024, and his FTA- Abs is positive. This description is most consistent with

Which hepatitis virus(s) below is (are) transmitted by the fecal/oral route?

Rapid immunological assays for Group A Streptococcus pyogenes antigen have a sensitivity of about 60% to 80% and a specificity of about 90% to 95% in pharyngitis infections. Given these data, which strategy below is optimal?

A positive test for hepatitis C antibody can be confirmed by or .

Which of the following non- treponemal tests must be read using a microscope?

Adults tend to have a poorer heterophile antibody response in infectious mononucleosis than children.

What advantage does countercurrent immunoelectrophoresis have over Ouchterlony double diffusion?

A chronic carrier of hepatitis B virus typically fails to develop the antibody and the antibody.

In general, rapid immunoassays for Legionella pneumophilia have the highest sensitivities and specificities when the specimen tested is

In the normal course of a hepatitis B virus infection, what is the order of appearance of the following markers in serum? 1. Hepatitis B surface antigen 2) Hepatitis B early antigen 3) Anti- hepatitis B surface antigen 4) Anti- hepatitis B early antigen 5) Anti- hepatitis B core antigen

A positive test for the presence of antibodies in a complement fixation test is

An advantage of using Staphylococcus aureus cells for coagglutination instead of liposomes is that a colored dye can be incorporated into the Staphylococcus aureus enhancing visualization of the agglutination.

Explain the properties of the Cowan 1 strain of Staphylococcus aureus that allow it to be a passive carrier of antibody in coagglutination procedures and how these properties contribute to an increased chance of false positive tests in some specimens.