A process that is required for some beauty treatments. Usually connected with hair colouring, brow and lash tinting and lash lifting. It is also recommended for waxing. It usually involves treatments that use oxidation in the chemical process. Manufacturers instructions should be followed with regards to the process and it is usually a requirement of any insurance policy. Dates and results must be recorded. Some recommend the test to be done on the inner elbow, others behind the ear. It is strongly recommended post COVID 19 and the vaccination as immune systems are often changed. It is NOT appropriate for nail coatings as all of these should not have any skin contact.