12. Precipitation (con't) and Agglutination

Question 1

What do the patterns of identity, non-identity, and partial identity in the Ouchterlony test look like?

Answer 1

Identity = arc
Non-identity = cross over
Partial identity = spur

Question 2

What does the spur formed in a partial identity reaction in the Ouchterlony test point to?

Answer 2

The spur points towards the least reacting / simpler Ag

Question 3

What kind of antigens are needed for agglutination reactions?

Answer 3

Ags must be particulate, or on a cell surface. (Insoluble)

ex: RBC, latex beads, gel particles coated with Ag, bacteria

Question 4

What are the particles in passive agglutination tests coated with?

Answer 4

Antigens are passively attached to latex bead

Question 5

What type of agglutination test would be appropriate to look for the heterophile antibody of infectious mononucleosis?

Answer 5

Active (Direct) Hemagglutination

Question 6

Some patients with thyroid disease produce antibodies to an antigen in the thyroid gland called thyroglobulin. What type of hemagglutination test could be used to detect this antibody?

Answer 6

Passive (Indirect) Hemagglutination

- adhere Ag to RBCs spontaneously or chemically.