Immunology: Common Lab Tests

Question 1

What do immunologic tests look for?

Answer 1

Specific infectious agents

Evaluate sensitivity & specificity

Question 2

Sensitivity

Answer 2

-Able to correctly identify all animals that are truly positive for a give reaction procedure
-How much of the antigen or antibody needs to be present before the color change
How sensitive is the test

Question 3

Specificity

Answer 3

Measures the number of false positives produced with a given reaction procedure
Can I determine exactly which protein this is?
Is there any cross reaction with a similar antigen?

Question 4

Which test has 100% sensitivity & 100% specificity?

Answer 4

No test exists

Question 5

What does the heartworm antigen test need to become positive?

Answer 5

A minimum of 3 adult female worms

Question 6

What sample do nearly all immunologic tests require?

Answer 6

Serum or plasma

Question 7

What sample should not be sent to the diagnostic lab?

Answer 7

Whole blood

Question 8

What route of collection is preferred?

Answer 8

Vacutainer to prevent hemolysis
Red top if serum
Lavender top if plasma unless otherwise noted

Question 9

Who has strict requirements and what must be done carefully and followed

Answer 9

The reference laboratories

The directions

Question 10

How should serologic samples be handled?

Answer 10

Clot for 20 to 30 minutes at room tep

Question 11

How long do you centrifuge serum samples for?

Answer 11

10 minutes at 1500 rpms or greater

Question 12

What sample do you centrifuge immediately after collection?

Answer 12

Plasma

Question 13

What do you pipette?

Answer 13

Serum or plasma into a transfer tube and label

Question 14

Can you freeze the serum or plasma samples?

Answer 14

Yes or refrigerate

Question 15

What is humoral immunity?

Answer 15

Antigen/antibody complexes

Question 16

What are the tests that look for antigen/antibody complexes (humoral immunity)

Answer 16

ELISA
CELISA
Latex Agglutination
Rapid Immunomigration & Immunochromatography

Question 17

ELISA

Answer 17

Enzyme-linked immunosorbent assay

Question 18

What is the most commonly used test in the veterinary practice?

Answer 18

ELISA

Question 19

What is an ELISA test?

Answer 19

Accurate way to detect specific antigens

viruses, bacteria, parasites, hormones

Question 20

What does the ELISA test test for?

Answer 20

Antigen in serum

Question 21

What does the test kit contain?

Answer 21

A specific antigen

Question 22

What are some examples of ELISA tests?

Answer 22

Heartworm
Feline leukemia
FIV
Parvo
Progesterone

Question 23

What is bound to the well walls, the test tray or the plastic wand of the ELISA test?

Answer 23

Monoclonal antibodies

Question 24

What happens in the ELISA test if the antigen is present?

Answer 24

It binds to the antibody & to a second enzyme-labeled antibody

Question 25

What happens if the antigen is present in the patient?

Answer 25

The antigen/antibody complexes will form and the enzyme will react and cause a color change

Question 26

What has to happen for the ELISA test to be positive?

Answer 26

The antigen needs to be present in the body and the antigen/antibody complexes need to be formed

Question 27

What is another ELISA test option

Answer 27

The test contains the specific antigen and then you are looking for the antibody in the sample from the patient

Question 28

What does it mean if the antigen is present?

Answer 28

We know it is a current infection

Question 29

What type of ELISA test is run on cats with suspected heartworm disease

Answer 29

The antibody test to look for the immune response because they might not have 3 adult female heartworms

Question 30

What is the problem with the ELISA antibody test that contains the antigen?

Answer 30

You don't know if it is a current infection or if they were previously infected

Question 31

CELISA tests

Answer 31

Competitive Enzyme-linked immunosorbent assay

Question 32

What is the CELISA test used for?

Answer 32

Equine infectious anemia

Question 33

What does the CELISA test use?

Answer 33

Patient antigen | enzyme-labled antigens as well as monoclonal antibodies

Question 34

What varies with antigen concentration?

Answer 34

Intensity of color | The more antigen present the more color you get

Question 35

What do we use the Latex agglutination test for?

Answer 35

Bovine brucellosis

Question 36

What does Latex agglutination test use?

Answer 36

Small, spherical latex particles that are coated with an antigen suspended in water

Question 37

What do the spherical particles do if the antibody is present?

Answer 37

Cause clumping

Question 38

RIM

Answer 38

Rapid Immunomigration or Immunochromatography | AKA lateral flow immunoassy

Question 39

What do RIM tests use?

Answer 39

Colloidal gold, enzymes, and color reagents or agglutinated latex particles

Question 40

What are present in the membrane of the test cassette where the sample is applied?

Answer 40

Antibodies

Question 41

Is there rinsing or reagent used in RIM tests?

Answer 41

No

Question 42

What do positive RIM results look like?

Answer 42

Two areas of color: | The test result and control

Question 43

What are examples of RIM tests

Answer 43

``` Heska heartworm Witness FeLV (feline leukemia virus) ```

Question 44

How does a RIM test different from an ELISA test

Answer 44

No diluent is needed, just the sample