Medical Device Sensitization Testing Services Following ISO 10993-10

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Sensitization (or allergic contact dermatitis) testing evaluates a medical device’s potential to cause an allergic or hypersensitivity reaction upon repeated or prolonged contact with tissue. Regulatory bodies worldwide, including the US FDA and EU Notified Bodies, require this assessment for nearly all medical devices that contact the patient for more than a transient period.

ISO 10993-10: Biological evaluation of medical devices – Part 10: Tests for skin sensitization provides the framework for this essential safety endpoint.

NAMSA, the global leader in medical device testing, offers comprehensive and recognized sensitization testing solutions—including modern in vitro and classical in vivo methods—to satisfy regulatory demands and accelerate your device’s market access.

Your ISO 10993-10 Sensitization Testing Strategy

The regulatory expectation is to use a tiered approach to sensitization, prioritizing non-animal in vitro methods when possible, as outlined in the most current regulatory guidance. NAMSA specializes in designing a risk-based testing program that minimizes time and maximizes compliance.

The Tiered Approach to Sensitization Testing

Tier	Test Method	Principle	Regulatory Acceptance
Tier 1 (In *Chemico/ In Vitro*)	Direct Peptide Reactivity Assay (DPRA)	Evaluates the potential of leachable chemicals to react directly with skin proteins, a key mechanism in the allergic response.	Increasingly accepted by global regulators as a screen and component of a weight-of-evidence approach.
Tier 2 (*In Vivo*)	Local Lymph Node Assay (LLNA)	The gold standard in vivo test. Measures cell proliferation in the draining lymph nodes after exposure to the device extract, providing a quantitative measure of allergic response potential.	Widely accepted globally, often required if chemical characterization or in vitro methods are inconclusive.
Tier 3 (*In Vivo*)	Guinea Pig Maximization Test (GPMT) or Buehler Test	Classical in vivo tests. Involve inducing and then challenging the animal to evaluate allergic potential.	Used when LLNA is inappropriate for the material or if specifically required by a regulatory body.

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Compliance and Expert Justification

Sensitization testing can be complex due to the varying material properties and the critical need for a conclusive result. Also, sensitization data rarely stands alone. Regulators expect a strong justification for the chosen test method and the interpretation of the results, especially when using in vitro screens. NAMSA offers the experience to manage this complexity.

Key Aspects of NAMSA’s Approach

Integrated with ISO 10993-18: Before any sensitization test, we often perform Chemical Characterization (ISO 10993-18) to identify and quantify the leachable substances. Knowing the chemical composition allows our toxicologists to potentially waive in vivo testing via a robust Toxicological Risk Assessment (TRA), saving you time and money.
Waiver Expertise: Our Board-Certified Toxicologists excel at developing scientific justifications (TRAs) to demonstrate that the concentration of potential sensitizers in your device is below recognized safe exposure thresholds, thereby supporting an in vivo testing waiver.
GLP/ISO Compliance: All sensitization testing is performed in our accredited laboratories under Good Laboratory Practice (GLP) to ensure the data is immediately accepted by the FDA, EMA, and other regulatory authorities worldwide.

Frequently Asked Questions (FAQs)

Sensitization testing evaluates a medical device’s potential to cause an allergic or hypersensitivity reaction, known as allergic contact dermatitis, upon repeated or prolonged exposure to the skin or tissue. It is required by global regulatory bodies (FDA, EMA) for virtually all devices that have direct or indirect patient contact for any significant duration to ensure patient safety against allergic reactions.

The shift to non-animal testing is encouraged, but regulatory acceptance is still tiered:

As a Screen: In vitro methods (like the Direct Peptide Reactivity Assay or DPRA) can be used as a valuable part of an integrated testing strategy (IATA).
For Waivers: If combined with ISO 10993-18 Chemical Characterization and a Toxicological Risk Assessment (TRA) that quantifies the leachable sensitizers and proves they are below safe thresholds, an in vivo test can often be waived.
When Required: If the chemical analysis is inconclusive or if the device is a high-risk implant, regulatory bodies typically still require the definitive Local Lymph Node Assay (LLNA).

The Local Lymph Node Assay (LLNA) is the current gold standard and the preferred in vivo method under ISO 10993-10 guidance. The LLNA is quantitative, requires fewer animals, and is more ethically acceptable than the older Guinea Pig Maximization Test (GPMT). The GPMT or Buehler Test is generally reserved for situations where the LLNA is technically inappropriate for the test material.

Yes. As with all biocompatibility endpoints, sensitization testing must be performed on the final, finished medical device following the final sterilization process. Sterilization residuals (especially from EtO) or material degradation caused by the process can introduce new sensitizing chemicals that must be evaluated to ensure product safety and regulatory compliance.

If a material is a known sensitizer, simply passing a standard sensitization test may be insufficient. You have two main options:

Material Substitution: The preferred solution is to replace the known sensitizing material with an alternative.
Risk Mitigation: If substitution is impossible, the manufacturer must provide a robust Toxicological Risk Assessment (TRA) and Extractables and Leachables (E&L) data to prove that the concentration of the sensitizing substance that the patient is exposed to is so low that the risk of an allergic reaction is negligible.