Not necessarily. Substances that appear to be mutagenic by the Ames test will require subsequent testing on higher-ordered organisms, such as animals. The Ames test assesses mutagenicity on bacterial colonies, which are prokaryotic cells. These lower-model organisms are not a perfect match to eukaryotic mammalian cells. Therefore, a substance classified as a mutagen by the Ames test might not necessarily be harmful to humans and further tests are required for any potential carcinogen identified in the test.