Are substances that test positive with the ames test necessarily carcinogenic in humans?

No, substances that test positive in the Ames test are not necessarily carcinogenic in humans. The Ames test assesses the mutagenic potential of a compound in bacteria, which can indicate a likelihood of carcinogenicity, but it does not directly correlate with human cancer risk. Many factors, including metabolism, exposure levels, and individual genetic differences, influence whether a substance causes cancer in humans. Therefore, while a positive Ames test result is a concern, further testing and evaluation are needed to determine actual carcinogenic risk.