Immunology: Reference Lab Tests

Question 1

What are the most common reference lab tests?

Answer 1

Coomb’s testing
Fluorescent Antibody Testing
Antibody titers
Polymerase Chain Reaction (PCR)

Question 2

What is a very specific test for IMHA?

Answer 2

Coombs’ test

Question 3

What does the Coombs’ test test for?

Answer 3

The presence of autoantibodies

Question 4

What are autoantibodies

Answer 4

Antibodies against the body

Question 5

What does a Direct Coombs’ test test for?

Answer 5

Detects antibodies that attack RBCs

Question 6

What is Coombs’ test based on?

Answer 6

The level of agglutination present

Question 7

What diseases does Immunodiffusion detect?

Answer 7

Equine Infectious anemia (retrovirus)

Johne disease

Question 8

What is Johne (Yoh-nee) disease?

Answer 8

Ruminant GI disease caused by mycobacterium

Question 9

What is present in the immunodiffusion test kit?

Answer 9

The antigen

Question 10

What is placed in the in separate wells on an agar plate in an immunodiffusion test?

Answer 10

The antigen and patient serum

Question 11

What diffue through the agar plate and form a band of precipitation where they meet in the Immunodiffusion test?

Answer 11

The antigen and patient serum

Question 12

What does it mean if no band is present in an immunodiffusion test?

Answer 12

No antibody present

Question 13

What is mainly used in research and diagnostic laboratories?

Answer 13

Radioimmunoassay

Question 14

What is the difference between radioimmunoassay and CELISA tests?

Answer 14

Radioimmunoassy uses a radioisotope instead of an enzyme

Question 15

How is Radioimmunoassay similar to CELISA?

Answer 15

It gives the amount of antigen present

Question 16

What is not common in veterinary practice but available in reference laboratories and used to verify a tentative diagnosis?

Answer 16

Indirect Fluorescent Antibody Testing

Question 17

Why do we run an IFA

Answer 17

To identify a specific antibody in a sample

Question 18

How does the direct antibody fluorescent antibody test work?

Answer 18

The patient sample is added to a fluorescent dye-conjugated antigen and if antigen/antibody complexes form (the disease is present) the sample will fluoresce

Question 19

What does an indirect Coombs test test for?

Answer 19

Detects antibodies that are already attached to red blood cells

Question 20

What does a positive Coombs test mean?

Answer 20

Immune-mediated hemolytic disease

Question 21

What kind of sample does the Radioimmunoassay test need?

Answer 21

Serum

Question 22

In Radioimmunoassay testing, how do patient antigen and labeled antigen affect each other?

Answer 22

With increasing amounts of patient antigen, more labeled antigen is displaced from the antibody

Question 23

In Radioimmunoassay testing what is compared with a standard curve to determine the concentration of the antigen?

Answer 23

Patient’s serum

Question 24

What kind of disease do we run the IFA to rule out?

Answer 24

Diseases that have no other tests to detect them

Question 25

What is a reason we run antibody titers?

Answer 25

To figure out if an animal has a current infection or if it has prior exposure to a specific antigen

Question 26

What do antibody titers determine the need of?

Answer 26

Revaccination

Question 27

How do you run an antibody titer?

Answer 27

WIth serial dilutions of each sample and examination of each dilution for the presence of antibodies

Question 28

What does a high titer mean?

Answer 28

Indicates an active infection

Question 29

What does a low titer mean?

Answer 29

Usually indicates a previous exposure to the specific antigen

Question 30

What are molecular diagnostic testing based on?

Answer 30

The testing of DNA or RNA

Question 31

What are DNA tests used for

Answer 31

Identify cancers Detect genetic defects Pedigrees Bacterial contaminants in foods

Question 32

What are the advantages of molecular diagnostics?

Answer 32

Increased sensitivity and specificity Small samples with faster results Factors that influence other procedures are not as crucial

Question 33

What are the disadvantages of molecular diagnostics?

Answer 33

Contamination gives false positives High levels of expertise to run tests Need more than one room to perform High costs

Question 34

Polymerace Chain Reaction (PCR)

Answer 34

Detect DNA segments | Widely used

Question 35

Reverse transcriptase polymerase chain reaction

Answer 35

Similar to PCR but tests single-stranded RNA

Question 36

What must be converted to a double-stranced DNA before the PCR process can continue?

Answer 36

The single-stranded RNA

Question 37

What are the benefits of running a Real-time Polymerase Chain Reaction?

Answer 37

Decreases the risk of contamination More easily automated Faster and easier to run Fluorescence probe attaches to DNA segments

Question 38

What else is the PCR called?

Answer 38

The amplification assay

Question 39

Why is the PCR called an Amplification Assay?

Answer 39

Because a small amount of DNA segment detected in the sample is amplified to run the test better and to determine the results

Question 40

What are the three steps of the amplification assay?

Answer 40

Denaturation Annealing Extension

Question 41

How often is this process repeated?

Answer 41

25 to 30 times to gain enough DNA

Question 42

Denaturation

Answer 42

Heated to break apart double stranded DNA | Each strand serves as a template for new nucleotides

Question 43

Annealing

Answer 43

Temperature is lowered | Causes primers to bind to separate strands

Question 44

Extension

Answer 44

Temperature raised again adn the Taq DNA polymerase causes new DNA segments to be produced

Question 45

What is Taq DNA polymerase

Answer 45

The enzyme can read DNA code and assemble the nucleotide base to form new complementary strands