14. Frequently asked questions

How to choose between animal testing methods?

The LLNA test is recommended as a first-line test because it uses quantitative measurements for cell counting or radioactivity measurement, allowing the dose-response relationship to be assessed. It therefore appears to be more reliable and is an alternative to the other two tests. Certain limitations may make it necessary to favor tests on guinea pigs (e.g., false negative results from the LLNA with certain metals, false positive results with certain skin irritants, particularly surfactants, or solubility of the test substance).

However, if a negative result is obtained with the LLNA, a guinea pig test (preferably a GPMT or Buehler test) should be performed using the method described in OECD Guideline No. 406.

Generally, the GPMT is used for active ingredients and the...