What Is Sensitization?
The sensitisation test evaluates the potential of substances released from the device to cause a delayed-type allergic reaction (contact allergy) after repeated contact. It differs from the irritation test: irritation involves direct tissue damage on first contact, whereas sensitisation involves sensitisation of the immune system and manifests on subsequent contact.
Purpose of Sensitization
The purpose is to determine the risk of the material causing allergic sensitisation in the user or patient.
Which Products Is Sensitization Applied To?
- Skin-contacting devices and adhesive products
- Gloves and medical textiles
- Catheters and implants
- Dental materials
- Wound-care products
In Which Sectors Is Sensitization Used?
Standards Related to Sensitization
- ISO 10993-10skin sensitivity assessment test
- ISO 10993-1
- ISO 10993-12
- OECD TG 429
- OECD TG 442
- ISO 11607end product sterile barrier packaging test
Sensitization Conditions
- Method selection
- The method appropriate to the device is chosen from options such as the guinea-pig maximisation test, closed-patch test, or LLNA
- Extraction
- Separate extracts are prepared with polar and non-polar solvents
- Stages
- Induction (sensitisation) and challenge phases
Equipment for Sensitization
- Animal housing and care infrastructure (if an animal method is applied)
- Extraction rig and incubator
- Patch-application materials
- Assessment and scoring equipment
Sample Requirements for Sensitization
- The specimen must represent the final, sterilised product
- Not raw material — the product that has gone through all manufacturing and sterilisation processes is submitted
- The specimen quantity is determined according to the surface-area/extraction ratio prescribed by the standard
- The device's type and duration of body contact must be stated
- The sterilisation method and, if applicable, residue information must be shared
Duration of Sensitization
The test takes several weeks owing to the induction and challenge phases; the total duration depends on the method chosen.
Sensitization Procedure
- 1The appropriate method for the device is selected under ISO 10993-10 and justified.
- 2The specimen is extracted with polar and non-polar solvents.
- 3The extract is applied repeatedly during the induction phase.
- 4A rest period is observed.
- 5The extract is reapplied during the challenge phase.
- 6Reactions are scored at defined time intervals.
- 7The result is evaluated by comparison with the control group.
Sensitization Acceptance Criteria
The acceptance criterion is that sensitisation findings, on the applied method's scoring system, show no significant increase relative to the control group. Scoring thresholds are defined in the standard for the chosen method.
Evaluation of Results
The result is interpreted comparatively against the control group. If the positive control does not give the expected reaction, the test is invalid.
Sensitization Report
- Applied standard and revision
- Specimen description, batch number and sterilisation method
- Extraction conditions (solvent, temperature, duration, ratio)
- Positive and negative control results
- Test results and grading
- Assessment and conclusion
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- MDR (EU) 2017/745
- Ethical and legal regulations on animal testing
Medikal Cihaz Testleri — What Does This Testing Field Cover?
The section below describes the field that the Sensitization test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Medical device testing shows that a device is safe for the patient and the user and maintains its intended performance. In this family safety is not only about avoiding harm; a device failing to perform its expected function is also treated as a risk. A monitor missing an alarm or a pump delivering the wrong dose is directly a patient safety event.
At the centre of the field is RISK MANAGEMENT, and this is what sets medical apart from other sectors. The risk management process run under ISO 14971 also determines which tests are required. The test list is not copied from a table of standards; it is derived and justified from the device's intended use, the nature and duration of patient contact, the use environment and foreseeable misuse.
Assessment consists of several separate bodies of work, each with its own set of standards. Biocompatibility runs through the ISO 10993 series, electrical device safety through the IEC 60601 series, sterilisation through ISO 11135/11137/17665, packaging through ISO 11607, software through IEC 62304 and usability through IEC 62366. The quality system (ISO 13485) is the framework that binds these together.
Which tests are required is determined by the device's CLASS and its MODE OF CONTACT WITH THE BODY. A product in brief contact with skin and an implant entering the bloodstream do not go through the same test set; the scope is set by a biological evaluation plan prepared under ISO 10993-1. That plan justifies in writing which endpoints are required and why the others are not.
Packaging and sterilisation are taken as seriously as the device itself in this field. For a sterile device the packaging is not a transport container but the barrier that maintains sterility; if the barrier is breached, the device is no longer sterile. Packaging processes are therefore validated and shelf life is supported by real-time ageing data.
For devices containing software, assessment shifts from testing towards PROCESS assurance. IEC 62304 defines which development and verification steps must be followed according to the safety class of the software; the evidence is the traceability of the development process. Testing software does not make it safe — the process record does.
The clinical side is a separate column of the technical file. Test reports show that the device is technically safe; clinical evaluation establishes that the device delivers the intended clinical benefit and that the benefit-risk balance is acceptable. Neither replaces the other.
Method groups in this field
Biocompatibility
Cytotoxicity, irritation, skin sensitisation, systemic toxicity, haemocompatibility, genotoxicity and local effects after implantation. The required endpoints are set by the ISO 10993-1 plan.
Electrical device safety
IEC 60601-1 basic safety and essential performance; EMC, alarm, usability and environmental requirements through the collateral standards.
Sterilisation validation
Validation of sterilisation processes by ethylene oxide, radiation or moist heat; bioburden and sterility assurance level studies.
Packaging
Integrity of the sterile barrier system, seal strength, distribution simulation and shelf-life studies.
Microbiological tests
Bioburden determination, sterility testing, bacterial endotoxin and, where required, carrier validation studies.
Software and usability
IEC 62304 life cycle evidence and use-error focused evaluation under IEC 62366.
Commonly confused in this field
- Cytotoxicity alone is not evidence of biocompatibility; the required set of endpoints is determined and justified according to ISO 10993-1.
- An ISO 13485 certificate does not confer CE marking; classification under the MDR, the technical file and the notified body process run separately.
- Accelerated ageing does not replace real-time ageing; a shelf life claim is supported by real-time data.
- A change of material (supplier, pigment, sterilisation method) may require the biological evaluation to be repeated; it is not a silent change.
- An assessment made without the collateral and particular standards for IEC 60601-1 is incomplete; which -1-x and -2-x standards were applied must appear in the report.
- In vitro diagnostic devices fall under the IVDR rather than the MDR, and laboratory equipment is often on the IEC 61010-1 side.
Which decisions these results support
- MDR/IVDR technical file and notified body assessment
- Completing the biological evaluation plan
- Sterilisation and packaging validation
- Determining shelf life and storage conditions
- Determining the scope of reassessment after a design change
Related Tests
Frequently Asked Questions About Sensitization
Can sensitisation testing be performed without animals?
Alternative in-vitro and in-chemico methods have been developed and regulatory acceptance is expanding. Acceptability for your device must be assessed within the framework of the applicable legislation and the notified body's expectations.
What is the difference between sensitisation and irritation?
Irritation is a direct, dose-dependent tissue reaction on first contact. Sensitisation is an immune-mediated response: sensitisation occurs on first contact, and the reaction appears on subsequent contact, at much lower doses.












