Agglutination Definition – the clumping together of antigen bearing cells, microorganisms or particles in the presence of specific antibodies. Particles may be RBCs (hemagglutination), bacterial cells (coagglutination) or inert particles such as latex or charcoal coated with antigen or antibody

Agglutination Reactions :Advantages Easy to carry out No complicated equipment needed Can be performed as needed Available in pre-package kits with controls Reactions are QUALITATIVE, i.e., positive or negative Titers can be performed to give semi-quantitative results

Agglutination (The Antigen is a Partiulate)… Qualitative: Slide Agglutination Tasts Semi Quantitative: Tube Agglutination Tests Semi Quantitative: Tube Agglutination Tests Qualitative: Primary Reaction (ELISA,…)

Slide Test Agglutination -- Qualitative Method Slide Test Agglutination -- Qualitative Method Latex agglutination Latex agglutination

Tube Test Agglutination -- Semi Quantitative Method Tube Test Agglutination -- Semi Quantitative Method Tube Agglutination Tests: Tube Agglutination Tests: Identify & Titrate antibodies in the patient’sserum.Titre: is defined as the reciprocal of the highest dilution of serum showing agglutination. 1/100 1/2001/400

Passive Agglutination Passive Agglutination Converting a precipitating test to an agglutinating test Chemically link soluble antigen to inert particles such as LATEX or RBC Addition of specific antibody will cause the particles to agglutinate Reverse PAT: antibody linked to LATEX e.g. Lancefield grouping in Streptococci.

Latex Rheumatoied Factor (IgM) Human IgG (Intact Ab) - Passive Agglutination

Antibody is attached to the particulate carrier. One of the most commonly used laboratory tests that involves latex particle agglutination is the procedure for C-Reactive Protein (CRP). - Reverse Passive Agglutination

Latex Latex CRP Anti CRP-Ab - Reverse Passive Agglutination

-- ELISA Quantitative Method