Clinical relevance: Diagnostic tools

Question 1

Direct test is to identify the __________. (IMPORTANT)

Answer 1

Antigen

Question 2

Indirect test is to identify the __________. (IMPORTANT)

Answer 2

Antibodies

Question 3

Why do we do a titer?

Answer 3

To see if it is an acute infection or convalescent and see if IgG vs IgM changes over time.

Question 4

___ is a diagnostic tool to ID the antigen.

Answer 4

DFA (direct fluorescent antibody)

Question 5

____ is a diagnostic tool to ID antibodies to the antigen.

Answer 5

IFA (indirect fluorescent antibody)

Question 6

What test is a common tool to detect/measure Ag or Ab?

Answer 6

ELISA

Enzyme linked ImmunoSorbant Assay

Question 7

Particulate antigens (rbcs) + antibodies = __________. (IMPORTANT)

Answer 7

Agglutination (looking for clumping to see a reaction, for strep throat, cryptococcus, for rapid diagnosis)

Question 8

What is Prozone?

Answer 8

A person who has lots and lots of antibody may detect negative in a test.

Question 9

3 distinct zones in Agglutination test reaction.

Answer 9

Prozone (antibody excess) (no clumping)
Equivalence (clumping)
Antigen excess

Question 10

Lattice theory

Answer 10

to have positive test, you need a lot of cross linking, equivalence

Question 11

How can excess antibody in blood still say negative?

Answer 11

So much antibody that the antigen didn’t have a time to cross link and agglutinate. If you dilute it way down, you can see positive.

Question 12

What is the name of something that that can lead to a negative test?

Answer 12

Prozone