What is the purpose of performing a predisposition check?

The purpose of performing a predisposition check, commonly known as a patch test, is to check for skin sensitivity. This test is crucial for identifying whether a client may have an allergic reaction to a product, particularly hair dyes or other chemical treatments that can cause adverse reactions. By applying a small amount of the product to a discrete area of skin (usually behind the ear or on the inner arm) and observing for any redness, itching, or irritation after a specified period, the cosmetologist can ensure the safety and comfort of the client before proceeding with the service.

Assessing hair growth, determining hair type, or evaluating scalp condition do not address potential reactions to the products being used, which is why they are not relevant to the predisposition check. Ensuring the client’s skin sensitivity is assessed is a critical step in preventing possible harm and maintaining professional standards in cosmetology practices.