Hvis weight-of-the-evidence-analysen viser, at stoffet har smertevoldende potentiale, eller hvis den indledende testning viser, at der vil komme en smertefuld reaktion, kan der bruges et lokalanæstetikum før instillation af teststoffet.
If the weight-of-the-evidence analysis indicates that the substance has the potential to cause pain, or initial testing shows that a painful reaction will occur, a local anaesthetic may be used prior to instillation of the test substance.