Ring Precipitin Test
Definition
A tube-based precipitin assay in which the antiserum is carefully underloaded beneath the sample; a ring of precipitate at the interface indicates a positive species match.
- Method
- Antiserum underlayered beneath the sample
- Positive sign
- Ring of precipitate at the interface
- Application
- Species-of-origin identification
Common questions
How does the ring precipitin test differ from the Ouchterlony double-diffusion test?+
The ring test relies on layering liquids in a capillary tube and reading a precipitate band at the interface within minutes, while Ouchterlony uses diffusion through a gel over hours to a day, generally giving sharper and more interpretable bands.
Why must careful layering technique be used in this test?+
Disturbing the interface while adding the sample can mix the two liquids prematurely, preventing the sharp precipitate ring needed for a clear positive result.
Related terms
- Antiserum (Pl. Antisera)
- Blood serum from an animal (typically a rabbit) that has been immunised against the proteins of another species. It contains antibodies that...
- Double Immunodiffusion (Ouchterlony)
- A gel diffusion method in which both antigen and antibody diffuse toward each other from separate wells in agar. Precipitin bands form...
- Precipitin Arc / Line
- The visible band of precipitate in an Ouchterlony plate where diffusing antigen and diffusing antibody meet. Its shape and relationship to adjacent...
- Precipitin Test
- A serological method in which an antiserum specific to one species' proteins is mixed with an extract of an unknown specimen. Formation...
- Spur Formation
- In Ouchterlony, a spur is formed when one arc curves beyond another due to an excess of a cross-reacting but non-identical antigen....