Page 1395 - Veterinary Immunology, 10th Edition

The measurement of antigen-antibody interactions for diagnostic
VetBooks.ir purposes is called serology.

Serological techniques can be classified into three broad
categories. Primary binding tests directly measure the binding of

antigen to antibody (Table 42.1). Secondary binding tests measure
the results of antigen-antibody interaction in vitro. These tests are
usually less sensitive than the primary binding tests but may be
simpler to perform or require less complex technology. The third

category, in vivo tests, measure the actual protective effect of
antibodies in an animal.

TABLE 42.1
Smallest Amount of Antibody Protein Detectable by Selected

Immunological Tests

Tests Protein (µg/mL)
Primary Binding Tests
ELISA 0.0005
Competitive radioimmunoassay 0.00005
Secondary Binding Tests
Gel precipitation 30
Ring precipitation 18
Bacterial agglutination 0.05
Passive hemagglutination 0.01
Hemagglutination inhibition 0.005
Complement fixation 0.05
Virus neutralization 0.00005
Bactericidal activity 0.00005
Antitoxin neutralization 0.06
In Vivo Test
Passive cutaneous anaphylaxis 0.02

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