A national validation study of the acute-toxic-class method--an alternative to the LD50 test.

In a national collaborative study an alternative to the classical LD50 test--the acute-toxic-class method--was validated. With this testing procedure mortality ranges are determined between defined dose levels that are used for classification and labelling in the European Community. The results were compared with LD50 data obtained from the literature which were categorized according to the defined dose levels. The results of this collaborative study have shown that the acute-toxic-class method allows allocation to the toxicity classes of very toxic, toxic, harmful and unclassified in the same manner as on the basis of the classical LD50 tests. The acute-toxic-class method uses fewer animals and subjects fewer animals to pain and distress than the LD50 test and yields the same information on toxic signs in the treated animals. Identical classifications were obtained by the six participating laboratories in 86% of the tests. This demonstrates that the acute-toxic-class method results in excellent reproducibility in comparison to the classical LD50 test and that this new method is a reliable alternative to the LD50 test.