Guinea-pig contact sensitization assays

After reviewing general aspects and the historical development of predictive animal skin sensitization tests, the recommended tests of the OECD and EC are discussed. Background information is given on the changes which occurred in the last 2 years. From the many factors known to influence induction and challenge of contact allergy in animals, the discussion is focused on the choice of induction concentration and the vehicle. The difference of general screening strategies in Europe and the USA is presented and discussed. The paper closes with a discussion on the importance of inhouse validation of the methods used for proper prediction of the sensitizing potential of chemicals and with remarks on predictive in vitro tests.