A predisposition test should be performed how many hours before a color service?

A predisposition test should be performed how many hours before a color service?

• A. 2 to 6
• B. 24-48
• C. 36-58
• D. 40-60

Answer: (B)

Check for potential allergy to color ingredients before applying dye. Doing the predisposition patch test 24–48 hours before the color service gives enough time for a delayed reaction to show up, which most often occurs within this window. If you wait too long after the test, you risk delaying the service; if you test too soon, a reaction might not yet appear. The test is applied to a small skin area (typically behind the ear or on the inside of the elbow) and observed for signs of redness, itching, or swelling during the 24–48 hour period. If no reaction occurs, you can proceed with the color service; if there is a reaction, adjust the product or skip that formulation for the client.

Check for potential allergy to color ingredients before applying dye. Doing the predisposition patch test 24–48 hours before the color service gives enough time for a delayed reaction to show up, which most often occurs within this window. If you wait too long after the test, you risk delaying the service; if you test too soon, a reaction might not yet appear. The test is applied to a small skin area (typically behind the ear or on the inside of the elbow) and observed for signs of redness, itching, or swelling during the 24–48 hour period. If no reaction occurs, you can proceed with the color service; if there is a reaction, adjust the product or skip that formulation for the client.