California Cosmetology Written ExamChemical Texture ServicesMedium
A salon in California is preparing to perform a formaldehyde-based keratin smoothing treatment on a new client. According to standard safety protocol and manufacturer guidelines, when should a predisposition (patch) test be performed relative to the service?
- AImmediately before applying the product on the day of service
- B24 to 48 hours before the scheduled service
- COnly after the treatment has been completed
- DOne hour before the service begins
Show answer & explanationAnswer & explanation
Correct answer: B. 24 to 48 hours before the scheduled service
A predisposition (patch) test should be applied to a small area of skin 24 to 48 hours before a chemical service to allow enough time to observe any allergic or sensitivity reaction before exposing the client to the full product.
Why the other options are wrong
- A. Testing immediately before does not allow time for a reaction to develop.
- C. Testing after exposes the client to risk before any allergy is known.
- D. One hour is too short a window for a reaction to manifest.
Predisposition (Patch) Test Timing
An allergy screening test applied to skin 24-48 hours before a chemical service to check for sensitivity reactions.
- Standard interval is 24-48 hours prior
- Applied to a small, discreet area of skin
- Required before many chemical services including formaldehyde-based treatments
Memory trick: Give the skin two days to 'sound the alarm' before the full service.