Page 155 - MNU microbiology theoritical 2025

General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025

Serology

• Serology is a branch of laboratory medicine that test infection in blood serum

by evaluating antigen-antibody reactions in vitro (Now using other body fluids)

• Serological testing: based on the concept that antibodies have specificity to

antigens.

➢ we can detect and identify unknown antibody using known antigen

➢ We can detect and identify unknown antigen using known antibodies.

➢

A- Agglutination Tests

Agglutination/Hemagglutination - When the antigen is particulate the

reaction of an antibody with the antigen can be detected by agglutination

(clumping) of the antigen. When the antigen is an erythrocyte the term

hemagglutination is used.

a) Qualitative agglutination test

- Agglutination tests can be used in a

qualitative manner to assess the

presence of an antigen or an antibody.

The antibody is mixed with the

particulate antigen and a positive test is

indicated by the agglutination of the

particulate antigen.

e.g. Blood grouping Test for; BG

antigen present on RBC

•

General Microbiology & Immunology (PM 401) theoretical handbook Page 144