Archives of Toxicology

, Volume 46, Issue 1, pp 41–44

The fluctuation test

  • B. A. Bridges

DOI: 10.1007/BF00361244

Cite this article as:
Bridges, B.A. Arch. Toxicol. (1980) 46: 41. doi:10.1007/BF00361244


The fluctuation test is an assay for the detection of mutation induction in bacteria by chemicals, carried out in liquid medium, and scored by counting the number out of around 50 tubes or wells that turn yellow. It is suitable for the Ames Salmonella strains or for Escherichia coli WP2 trp and its derivatives. Calcium precipitated microsomes, S9 fraction or freshly prepared hepatocytes can be incorporated for metabolic activation. It is comparable to the Ames test in its ability to detect mutagens and carcinogens and generally shares the limitations of that test as regards extrapolation to animals and man. Its disadvantages are that it is marginally slower and slightly more labour intensive than the Ames protocol. For certain applications, however, these disadvantages may be offset by the advantages of somewhat greater sensitivity, ability to be automated, and facility for using hepatocytes for metabolic activation. The test is particularly suitable for the testing of aqueous samples containing low levels of mutagen.

Key words

Bacterial mutation2-acetylaminofluoreneHepatocytes, metabolic activation byMicrosomes, metabolic activation by

Copyright information

© Springer-Verlag 1980

Authors and Affiliations

  • B. A. Bridges
    • 1
  1. 1.MRC Cell Mutation UnitUniversity of SussexFalmerGreat Britain