The Guinea pig maximisation test (GPMT) is an ''

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, an ...

'' test to screen for substances that cause human skin sensitisation (i.e.

allergens An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response. In technical terms, an allergen is an antigen that is capable of stimulating a type-I hypersensitivi ...

). It was first proposed by B. Magnusson and Albert Kligman in 1969 and described in their 1970 book ''Allergic Contact Dermatitis in the Guinea Pig''. The test is composed of two phases, the induction phase and the challenge phase. The induction phase includes exposing a test group of animals twice to the test material, first by intradermal injection followed by topical application seven days later. During Induction A, the test animals are exposed intradermally to the test material, along with an

adjuvant In pharmacology, an adjuvant is a drug or other substance, or a combination of substances, that is used to increase the efficacy or potency of certain drugs. Specifically, the term can refer to: * Adjuvant therapy in cancer management * Anal ...

to enhance the immune reaction of the guinea pig. During Induction B, the topical induction, the test group is exposed to the test article for 48 hours, occluded. 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. 20 animals would typically be used to ensure against

false negative A false positive is an error in binary classification in which a test result incorrectly indicates the presence of a condition (such as a disease when the disease is not present), while a false negative is the opposite error, where the test resu ...

results. The

OECD Guidelines for the Testing of Chemicals OECD Guidelines for the Testing of Chemicals (OECD TG) are a set of internationally accepted specifications for the testing of chemicals decided on by the Organisation for Economic Co-operation and Development (OECD). They were first published in ...

guideline No. 406 of 1992. The test has been largely superseded by the murine

local lymph node assay The murine local lymph node assay (LLNA) is an ''in vivo'' test for skin sensitisation. LLNA has largely superseded the guinea pig maximisation test and the Buehler test. It is considered more scientific and less cruel (lower number of animals; ...

. D.A. Basketter and E.W. Scholes reviewed them in 1992 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. Only in exceptional circumstances should another test be used. Justification for the use of another test shall be provided."

References

{{reflist Allergology