Asistencia Médica Especializada Polizas a medida Tecnologías avanzadas

Safety studies - Patch test, Open test y Test de uso.

Patch Test


Patch Test (PT) corresponds to a skin compatibility study, as confirmation of previous data obtained in in vitro studies. PT consists in a unique application under occlusion (with a patch) of a cosmetic product, on the back of the volunteer. A second patch is also applied to discard any reaction to the patch itself. This patch must remain on the skin during 48 hours, afterwards the patch is removed by the dermatologist and the aspect of the skin is evaluated after 30 minutes: erythema, edema, papule/ vesicles/ ampoules/pustules, reflectivity, dryness/desquamation, detergent effect.

Open Test


This test is performed when, due to the specificity of a cosmetic, an occlusive test (Patch Test) cannot be performed.

The test consists in the unique or repeated application of the study product on the internal part of forearm – in case of dermatological compatibility, or around the eye mucous membrane, in the mouth or in the external intimate area. The reactions are observed on the skin or mucosa after 30 minutes or one hour of application, as well as after 24 and 48 hours after application.

Open Test allows diagnose visible irritative reactions (clinical signs), followed by a macroscopic exam performed according to the established numeric scale. Likewise it may also retrieve sensations of discomfort described by the volunteers.


Test de Uso

In-Use Test, also known as Test of Acceptability, are developed under dermatological control (volunteers examined individually by a Dermatologist) or under pediatric control (in children), under gynecological control (intimate hygiene products), under ophthalmological control (products in contact with eye mucosa), or under dentist control (mouth hygiene products). Such studies allow verify the absence of reactions of discomfort and cumulative irritation (functional and physical signs) associated with the application of the study product, during 2 to 4 weeks, in normal use condition, in volunteers which comply with specific inclusion and exclusion criteria. This study is normally follows a Patch Test when the results are negative (not irritant) or a weak positive reaction exists (slightly irritant), as it confirm clinical significance of a previous Patch Test.