24th Page

Question 1

What is agglutination?

Answer 1

A process by which particulate antigens such as cells aggregate to form larger complexes when a specific antibody is present.

Question 2

What are the steps involved in agglutination?

SL

Answer 2

1. Sensitization
2. Lattice Formation

Question 3

The first reaction involves Ag-Ab combination through SINGLE antigenic determinants on the particle surface.

Answer 3

Sensitization

Question 4

The sum of interactions between antibody and MULTIPLE antigenic determinants on a particle depends on environmental conditions and the relative concentrations of Ag and Ab.

Answer 4

Lattice Formation

Question 5

What are the types of agglutination reactions?

Answer 5

1. Direct agglutination
2. Passive agglutination / Indirect agglutination
3. Reverse passive agglutination
4. Coagglutination
5. Agglutination inhibition
6. Hemagglutination inhibition

Question 6

What is direct agglutination?

Answer 6

Agglutination where antigens are found NATURALLY on a particle.

Example: Kauffmann and white scheme (Widal Test) for Salmonella serotyping.

Question 7

What is hemagglutination?

Answer 7

Agglutination reaction that involves RBCs.

Example: ABO typing of human RBCs, test for Febrile agglutinins such as Widal.

Question 8

What is passive agglutination?

Answer 8

Antigen is attached to a CARRIER particle such as latex, bentonite, charcoal, and RBC

Agglutination occurs if patient Ab is present.

Example: Rheumatoid factor, ASO, Antinuclear Ab and antibodies to Trichinella.

Question 9

What is reverse passive agglutination?

Answer 9

Ab rather than antigen is attached to a carrier particle.

Agglutination occurs if patient antigen is present.

Used to detect microbial antigens.

Question 10

What is coagglutination?

Answer 10

Uses BACTERIA as the inert particles to which Ab is attached.

S. aureus is most frequently used, because it has a protein on its outer surface (protein A), which naturally adsorbs the Fc portion of IgG molecules.

Question 11

What is agglutination inhibition?

Answer 11

Reactions are based on competition between particulate and soluble Ags for LIMITED Ab-combining sites.

Lack of agglutination is an indicator of a positive reaction.

Example: human chorionic gonadotropin (hCG) test.

Question 12

What is hemagglutination inhibition?

Answer 12

RBCs are the indicator particles used to detect antibodies to certain viruses.

Examples include Rubella, Mumps, Measles, Influenza, Parainfluenza, HBV, Herpes, Respiratory Syncytial virus, and Adenovirus.

Question 13

What is the purpose of Antiglobulin-Mediated Agglutination / Coomb’s Test?

Answer 13

Detects non-agglutinating antibodies by means of coupling with a SECOND antibody.

Question 14

DAT

Answer 14

Investigation of Hemolytic Disease of the Newborn (HDN)

Hemolytic Transfusion Reactions (HTR)

Diagnosis of Autoimmune Hemolytic Anemia (AIHA), Diagnosis of Drug-Induced Hemolytic Anemia,

Question 15

IAT

CAARD

Answer 15

Crossmatching
Antibody Detection
Antibody Identification
RBC Antigen Phenotyping such as Du / Weak D typing.

Question 16

What are the types of AHG preparation?

PM

Answer 16

1. Polyclonal Antibodies
2. Monoclonal Antibodies

Question 17

prepared by conventional technology using rabbits, goats

Answer 17

Polyclonal Antibodies

Question 18

prepared by hybridoma technology using mice as source of antibodies

Answer 18

Monoclonal Antibodies

Question 19

What is Polyspentic AHG?

Answer 19

Contains anti-IgG and Anti-C3d.

Question 20

What is Monospecific AHG?

Answer 20

Contains either anti-IgG or Anti-C3d.

Question 21

What are O Check Cells?

Answer 21

Group O Rh positive RBC, sensitized with IgG/ Anti-D, added to negative AHG tests to validate the negative reaction.

Question 22

What does a negative AHG reaction indicate?

Answer 22

No agglutination, which may be invalid due to reasons such as

neutralized and inactivated AHG reagent, expired AHG reagent, or
omission of AHG reagent.

Question 23

What does a positive AHG reaction indicate?

Answer 23

Agglutination, indicating VALID TEST, done properly and there is no sensitization of patient’s antigen or RBC.

Question 24

How is agglutination graded?

Answer 24

0: No agglutinates,
W+: Many tiny agglutinates/many free cells/ may not be visible in microscope
1+: Many small agglutinates/ many free cells
2+: Many medium-sized agglutinates/ moderate free cells
3+: Several large agglutinates/ few free cells
4+: One large, solid agglutinate/ no free cells

Question 25

What is the appearance of the supernate in different grades of agglutination?

Answer 25

0: Dark, turbid, homogenous;
W+: Dark, turbid;
1+: Turbid;
2+: Clear;
3+: Clear.
4+: Clear

Question 26

Examples of Antigens in direct agglutination

Answer 26

Kauffman
White scheme (widal test) for salmonella serotyping

Question 27

Example of hemagglutination

Answer 27

ABO typing of human RBCs
Test for Febrile agglutinins such as Widal

Question 28

Example in Passive Agglutination

R 3A

Answer 28

Rheumatoid factor
ASO
Antinuclear Ab
antibodies to Trichinella

Question 29

In coagglutination, what is the most frequently used bec. it has a protein on its outer surface (protein A) which absorbs the Fc portion of b (IgG except IgG3) molecules

Answer 29

S. aureus

Question 30

Involves haptens that are complexed to proteins

Example: hCG test

Answer 30

Agglutination Inhibition

Question 31

Examples of viruses being detected in Hemagglutination inhibition

Answer 31

Rubella
Mumps
Measles
Infuenza
Parainfluenza
HBV
Herpes
Respiratory Synctial virus RSV
Adenovirus

Question 32

spontaneous agglutination occurs because virus particles links to RBCs together in Hemagglution inhibition

Answer 32

TRUE