What Is Sterilization Validation?
Sterilisation validation proves that the applied sterilisation process achieves the targeted sterility assurance level (SAL) on the product. In medical devices the target SAL is generally 10⁻⁶: a probability of at most one in a million products retaining a viable microorganism. This level is demonstrated not by testing but by process validation.
Purpose of Sterilization Validation
The purpose is to prove that the sterilisation process reproducibly achieves sterility with defined parameters and does not damage the product.
Which Products Is Sterilization Validation Applied To?
- Sterile single-use medical devices
- Implants
- Surgical sets and drapes
- Syringe and catheter sets
- Reusable devices (steam sterilisation)
In Which Sectors Is Sterilization Validation Used?
Standards Related to Sterilization Validation
- ISO 11135
- ISO 11137-1
- ISO 11137-2
- ISO 11137-3
- ISO 17665-1
- ISO 11737-1determination of microbial load in medical devices test
- ISO 11737-2sterility test in sterilization verification test
- ISO 10993-7
- ISO 11607end product sterile barrier packaging test
Sterilization Validation Conditions
- Method
- Ethylene oxide (ISO 11135), radiation (ISO 11137), or moist heat (ISO 17665)
- SAL target
- Commonly 10⁻⁶ in medical devices
- Dose setting
- For radiation, using approaches such as VDmax or Method 1 in ISO 11137-2; based on bioburden
- EO residue
- Ethylene oxide and ethylene chlorohydrin residue limits under ISO 10993-7
Equipment for Sterilization Validation
- Steriliser (EO, gamma/E-beam facility, or autoclave)
- Biological indicators and chemical indicators
- Dosimeters (for radiation)
- Temperature and humidity measurement systems
- Microbiology laboratory
- Gas chromatography (for EO residue)
Sample Requirements for Sterilization Validation
- The product together with its final packaging
- Worst-case load configuration
- Bioburden data must be available
- Product-family description and rationale for the hardest-to-sterilise product
- The number of specimens is determined as prescribed by the standard
Duration of Sterilization Validation
Typically several months, together with the IQ/OQ/PQ stages and microbiological studies.
Sterilization Validation Procedure
- 1The sterilisation method is chosen and product compatibility is assessed.
- 2Bioburden is determined (ISO 11737-1).
- 3Installation qualification (IQ) is performed.
- 4Equipment parameter ranges are verified through operational qualification (OQ).
- 5Performance qualification (PQ) is carried out with the product.
- 6Dose-setting studies are performed for radiation, and half-cycle and biological-indicator studies for EO.
- 7Verification is performed with the sterility test (ISO 11737-2).
- 8Residue analysis is carried out for EO.
- 9The product's post-sterilisation function and packaging integrity are verified.
- 10A routine-monitoring and revalidation plan is established.
Sterilization Validation Acceptance Criteria
The acceptance criterion is demonstrating, by the relevant standard's method, that the targeted sterility assurance level (commonly SAL 10⁻⁶) has been achieved. For EO sterilisation, the residue limits in ISO 10993-7 must also be met.
Evaluation of Results
Results are interpreted by evaluating process parameters, bioburden data and product compatibility together. The sterility test alone is not considered sufficient evidence; the primary evidence is process validation.
Sterilization Validation Report
- Sterilisation method and target SAL
- Product-family description and worst-case rationale
- Bioburden data
- IQ/OQ/PQ results
- Dose-setting or cycle-development data
- Sterility test and biological-indicator results
- EO residue analysis (if applicable)
- Product and packaging compatibility results
- Routine-monitoring and revalidation plan
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
- ISO 13485 process validation
- ISO 10993-7 EO residue limits
Medikal Cihaz Testleri — What Does This Testing Field Cover?
The section below describes the field that the Sterilization Validation 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 Sterilization Validation
What does SAL 10⁻⁶ mean?
It means the probability of a viable microorganism being present on a product after sterilisation is no more than one in a million. This is a probability statement and cannot be measured by testing; it is calculated from the process's microbial-kill kinetics and demonstrated through validation.
When is revalidation required?
Revalidation is performed when there is a change in product design, material, packaging, load configuration or sterilisation parameters; when a significant increase in bioburden is observed; and at the periodic intervals prescribed by the standards.
Why is EO residue measured separately?
Ethylene oxide is a toxic and mutagenic substance; residue remaining in the product transfers to the patient. ISO 10993-7 defines permitted daily exposure limits according to contact duration, and requires the aeration time to be validated so as to meet these limits.