It was first proposed by B. Magnusson and Albert Kligman in 1969[1] and described in their 1970 book Allergic Contact Dermatitis in the Guinea Pig.
The guinea pigs are then a short while later exposed to a lower concentration of the test material, and their allergic reaction, if any, measured.
15% of guinea pigs must show a reaction for the test to be considered positive.
[3] The test has been largely superseded by the murine local lymph node assay.
Scholes reviewed them in 1992[4] The REACH Regulation, Annex VII, paragraph 8.3 states "The Murine Local Lymph Node Assay (LLNA) is the first-choice method for in vivo testing.