Open Application Patch Test

Welcome to our open application patch test service page! The open application patch test (OAPT) is a simple way to detect allergic contact dermatitis (delayed type allergy or type 4 hypersensitivity).

Protheragen-ING ensures the safety and compliance of your cosmetics with our reliable cosmetics OAPT service.

Which Products Are Suitable for Testing?

In general, closed patch testing is commonly used for cosmetics.

Under special circumstances, such as freckle-removing cosmetics and powdery (such as powder, foundation) sunscreen cosmetics, when human skin patch tests produce irritating results or the results are difficult to judge, OAPT should be added.

The OAPT is also applicable to rinse-off products, hair dyes, hair removal, and other products.

Open Application Patch Test Sample.

Comprehensive OAPT Services

Protheragen-ING specializes in OAPT research for cosmetics. Our comprehensive services include but are not limited to the following.

Protocol Development

We work with you to develop a custom OAPT protocol that meets your specific product and regulatory requirements. We consider factors such as duration of exposure, dose, field of application and evaluation criteria.

Patch Application and Observation

We apply the test sample to designated areas of the skin according to the protocol and closely observe the skin for any signs of irritation, such as erythema, edema, or other visual abnormalities, for the designated period of time.

For equivocal or weakly positive results from open application testing, or to determine whether a mildly positive result is clinically relevant, we will perform formal patch testing to identify the specific contact allergen.

Assessment and Scoring

We systematically evaluate test results based on predefined scoring criteria or scoring systems. This allows for consistent and objective assessment of skin response, ensuring data is reliable and comparable.

Data Analysis and Reporting

Protheragen-ING performs thorough data analysis and generates comprehensive reports. The report includes detailed information about the test method, observed reactions, and interpretation of the results. We provide clear conclusions and recommendations based on our findings.

Open Application Patch Tests.

Test Procedure

Open test

The product can be applied directly or dissolved in water or other solvents and applied freely to the skin.

They are recommended as a first step when unknown or little studied substances need to be tested.

Semi-open test

This method is designed to evaluate products that may be irritating due to the presence of solvents or emulsifiers.

Use a cotton swab to apply a small amount of product to a 2x2cm area. Once completely dry, cover the area with tape for two days. The site will be re-evaluated after 48 and 96 hours.

Repeated open application test (ROAT)

For more information or to discuss your specific requirements, please contact us today. We will respond within 2-4 working days.

We look forward to working with you to meet your testing needs and contribute to the success of your cosmetic formulations.


Daily: 9.30 AM–6.00 PM
Sunday : 9.30 AM–1.00 PM
Holidays: Closed

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