Exam 1: Indirect Methods Flashcards
What are indirect methods of testing?
ELISA Indirect immunofluorescence Agar gel immunodiffusion (AGID) Hemagglutination Hemagglutination Inhibition
How are antibody titers expressed?
As the neutralization index (alpha test procedure) or as the highest dilution that protects 50% of the test host against a precalculated dose (beta test procedure)
What is a positive serologic test?
A 4 fold rise in titer over a 2-3 week period
How is the neutrilization titer expressed?
As the reciprocal of the highest dilution at which virus infection is blocked
How does indirect immunofluorescence work?
A fluorescent labeled antiglobulin is used to detect serum antibody bound to an antigen
How does the AGID double diffusion test work?
A circular concentration gradient is established for each reactant and these eventually overlap
Optimal proportions for the occurrence of precipitation will occur in one zone of the superimposed gradients
When can detection of virus-induced hemagglutination be used?
As a preliminary test when attempting to identify a virus, while inhibition of this phenomenon by antibody may be employed as a method of identifying a specific virus or to measure antibody levels in serum
