Patch testing devices, manufactured by specialized firms, are varied. They are used concurrently in dermatological clinics, without having a mandatory standardisation shall be imposed.

The qualifications for a determined testing equipment are as follows:

• inertia on the allergenic plan
• absence of irritability of the integument by patch testing equipment
• adheres to the seed coat during the 48 hours of application
• surface of reasonable size to avoid any discomfort to the patient and to allow the simultaneous achievement of a high number of patch testing

For a long time, testing materials included the following three (3) components:

• the pellet which acts as support to the test substance
• the white washer
• the adhesive plaster