It provides valuable insights into the clients skin sensitivity, healing, response, and hair type. It allows the practitioner to observe risk of injury during full treatment.

A patch test is performed to check whether a client may have an allergic reaction or sensitivity to a product, treatment, or active ingredient before it is used more widely on the skin. A small amount of the product is applied to a discreet area, such as behind the ear or on the inner arm, and left for a specified period of time.