Postzone effect
Definition
A false-negative serological result caused by antigen excess. When antigen greatly exceeds antibody, both binding sites on each antibody molecule are occupied by separate antigen molecules, again preventing cross-linking and lattice formation. Also called the antigen excess effect.
Related terms
- Complement
- A group of heat-labile serum proteins (approximately 30 proteins, designated C1 through C9 in the classical pathway) that can be activated by...
- Complement fixation
- The binding and consumption of complement proteins by an antigen-antibody immune complex. Once fixed, complement is no longer available for the lytic...
- Cross-reactivity
- The capacity of an antibody raised against one analyte to bind structurally related compounds. In RIA, cross-reactivity is the main driver of...
- Indicator system
- In the complement fixation test, sheep red blood cells pre-coated with anti-sheep-RBC antibody (sensitised cells). These cells are lysed by free complement...
- Prozone effect
- A false-negative serological result caused by antibody excess. When antibody concentration is too high relative to antigen, antibodies saturate individual antigen molecules...
Explained in
- Complement Fixation and Mixed Antigen-Antibody ReactionsA false-negative serological result caused by antigen excess. When antigen greatly exceeds antibody, both binding sites on each antibody molecule are occupied...