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

A predisposition test, commonly referred to as a patch test, is essential in evaluating a client's sensitivity to hair color products. Performing this test 24-48 hours before a color service allows enough time to observe any allergic reactions without delaying the scheduled appointment. This timeframe is crucial because it provides a buffer period for any potential adverse effects to manifest, ensuring the safety of the client during the hair coloring process.

Conducting the test within this 24-48 hour window enables hairstylists to assess reaction possibilities while minimizing the risk of discomfort or harm during the actual service. If done too far in advance, the results may not accurately reflect the client's current skin sensitivity, as allergic reactions can develop over time. Testing just an hour before the color service is insufficient, as it does not allow adequate observation time for any delayed reactions. Thus, the prescribed 24-48 hour window is both a practical and safety-oriented standard in the hairstyling industry.