2 Serology

Question 1

Which ELISA is the MOST COMMON?

Which ELISA probes for antibodies to an antigen..labeled antibody binds to unlabeled antibody?

Answer 1

sandwich ELISA

Indirect

Question 2

What do you have when the test screams positive for something, but the results are NEGATIVE?

Answer 2

PROZONE

Antibody titer so high, agglunation test is NEGATIVE!

Question 3

(LO) Whqt’s the viral window?

What’s the significance of IgG and IgM in serology?

For an acute titer you would use Ig_ and the ratio would be around 1:4.

For a convalescent titer, it’s somewhere around 1:__ or higher and is collected a couple weeks later from the same person

Answer 3

In the viral window, it’s the time where your body isn’t producing antibodies for what you’ve just been infected with so it’s doing the most damage

IgG is a Past infection marker.
IgM is an acute/ current infection marker

Acute titer is IgG

1:16 or higher would be a convalescent titer

Question 4

(LO) Define the term

Answer 4

Enzyme linked immunosorbant assay

Direct probes for ANTIGEN

Indirect probes for ANTIBODIES

Unlabeled ‘primary antibody (human serum, possible containing antibody to x”). Reported by anti-human IgG, into colorless substrate

Question 5

(LO) Identify the purpose of performing a direct fluorescent antibody (DFA) test vs
an indirect fluorescent antibody (IFA)

Answer 5

.DFA we are detecting ANTIGEN. Light up specific cells or micro organisms.

IFA we are detecting ANTIBODY!! IgG added… ID antibodies to the antigen

Question 6

(LO) Interpret a precipitin curve, explaining the significance of prozone,
equivalence zone, and antigen excess zone in determining a positive agglutination test.

Answer 6

Serum is diluted with saline and fixed amount of antigen is added to each tube for the curve.

PROZONE is antibody excess

Curve goes from AB +++ (PROZONE), AB+, Ag: AB (Middle: equivalence zone of optimal proportions), AG+, AG +++ (antigen excess)

Antibody titer so high, agglutination test is NEGATIVE