Ouchterlony Double Diffusion
Definition
A gel diffusion technique in which antigen and antibody placed in separate wells in an agar gel diffuse passively toward each other. A precipitation arc forms at the zone of equivalence. Also called immunodiffusion or the Ouchterlony technique after its developer, Orjan Ouchterlony.
- Also called
- Immunodiffusion, Ouchterlony technique
- Developer
- Orjan Ouchterlony
- Method
- Antigen and antibody diffuse toward each other in agar gel
- Positive result
- Precipitation arc at the zone of equivalence
Common questions
What does the shape of the precipitation line reveal beyond a simple positive result?+
When wells with different antigens are compared against a common antibody, the pattern where lines fuse, cross, or form spurs indicates whether the antigens are identical, unrelated, or partially related, which is useful for species and antigen comparison work.
Why has Ouchterlony double diffusion largely been replaced by other methods in modern labs?+
It is slow, often taking 24 to 48 hours for diffusion and precipitation to develop, and less sensitive than newer immunoassay techniques, so labs now favour faster methods for routine species-of-origin testing and reserve it mainly for confirmatory or teaching use.
Related terms
- Precipitin Reaction
- The formation of an insoluble antigen-antibody complex (precipitate) when soluble antigen and antibody meet at equivalent concentrations. The Ouchterlony double-diffusion test and...
- Anti-Human Serum
- Antibodies raised in a rabbit (or goat) by repeated injection of human serum. The rabbit's immune system makes IgG against human serum...
- Antigen-Antibody Reaction
- The specific non-covalent binding between an antigen (a molecule capable of eliciting an immune response) and the antibody produced against it. In...
- Antiserum
- Serum collected from an immunised animal containing antibodies directed against a specific antigen or group of antigens. In species identification, antiserum raised...
- COI Barcoding
- DNA-based species identification using a standard 658 bp segment of the mitochondrial cytochrome oxidase subunit I gene. Sequences are matched against reference...
- Counter-Immunoelectrophoresis (CIE)
- An accelerated form of gel diffusion in which an electric current drives antigen and antibody toward each other rather than relying on...
- 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...
- Cyt-B PCR
- Amplification and sequencing of the mitochondrial cytochrome-b gene. The reference marker for species identification in degraded and trace samples.
- Immunoelectrophoresis
- A two-step technique: proteins are first separated by electrophoresis in agar gel, then antiserum diffuses from a parallel trough and forms precipitin...
- Uhlenhuth Test (1901)
- The original precipitin ring test devised by Paul Uhlenhuth in Greifswald. Layering anti-human serum under a dilute bloodstain extract gives a white...
- Zone of Equivalence
- The concentration range at which antigen and antibody molecules are present in the correct ratio for maximum lattice formation and visible precipitation....
Explained in these topics
- Determination of Species of Origin from Blood and Body FluidsAntigen and antibody diffuse from separate wells in an agar gel; a precipitin line forms where they meet at equivalence. Useful for comparing several antisera...
- The Precipitin Test for Species Identification