Validation of Sterilization Processes
[ISO 13485 Cl, 7.5.9]
This clause ensures that any sterilization process used for medical devices is:
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Validated before routine use,
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Consistently controlled,
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Capable of achieving the required sterility assurance level (SAL),
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Documented and maintained throughout the product life cycle.
Because you cannot fully verify sterility by inspection or testing of every product, the process itself must be scientifically validated to prove it consistently produces sterile outcomes.
Key Requirements of Clause 7.5.9
The organization must Validate the sterilization process before use
- Validation must demonstrate that the process can reliably achieve the specified Sterility Assurance Level (SAL), typically 10⁻⁶ for medical devices.
- Use industry-recognized standards such as ISO 11135 – Ethylene oxide (EtO), ISO 11137 – Radiation sterilization, ISO 17665 – Moist heat (steam) sterilization, ISO 20857 – Dry heat sterilization
- Maintain documented procedures and records: Procedures for validation, revalidation, and routine control and Records for all validation activities (IQ, OQ, PQ) and periodic monitoring.
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Revalidate when changes occur any change in device design, packaging, materials, equipment, or load configuration requires revalidation.
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Establish controls for sterile barrier systems, packaging and sealing processes must protect against contamination and maintain sterility up to the point of use.
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Document evidence of control- Records showing sterilization cycle parameters (temperature, pressure, exposure time, gas concentration, etc.) meet specifications.
Validation Phases: Sterilization validation generally includes three documented stages:
| Phase | Purpose |
|---|---|
| IQ – Installation Qualification | Verify that sterilization equipment and utilities are installed correctly and meet specifications. |
| OQ – Operational Qualification | Confirm that the sterilizer operates within defined limits and all instruments work as intended. |
| PQ – Performance Qualification | Demonstrate consistent sterilization results under routine operating conditions using actual product loads. |
Revalidation is required when:
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There’s a change in sterilizer model or location
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Packaging material or design changes
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Load configuration or density changes
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Cycle parameters are modified
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A significant deviation is found during process monitoring
Common Audit Findings (Nonconformities)
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Incomplete or missing sterilization validation reports.
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Failure to perform revalidation after equipment or packaging changes.
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Inadequate documentation of routine monitoring (e.g., temperature or gas exposure logs).
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Lack of defined acceptance criteria in validation protocol.
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No evidence of personnel training on sterilization validation procedures.
The records to Maintain are Sterilization validation protocol and report (IQ/OQ/PQ), Sterilizer calibration and maintenance logs, Sterilization batch records, Biological indicator (BI) and chemical indicator (CI) test results, Sterile barrier integrity testing results and Revalidation and deviation reports
Clause 7.5.9 ensures that sterility is not just tested it’s built into the process so manufacturers must scientifically prove that every sterilization cycle delivers the required SAL and that controls remain consistent, documented, and periodically reviewed.
Frequently Asked Questions
What is the Sterility Assurance Level (SAL), and what value is typically required?
The Sterility Assurance Level (SAL) is the probability of a single viable microorganism being present on a product after sterilization.
For medical devices, the typical requirement is SAL ≤ 10⁻⁶, meaning there’s less than one chance in a million that a viable microorganism remains.
Why is sterilization process validation necessary under ISO 13485?
Because sterility cannot be confirmed by inspecting or testing every product, the sterilization process itself must be validated to ensure it consistently achieves the required Sterility Assurance Level (SAL). Validation provides scientific evidence that the process is capable, controlled, and reproducible.
Which standards are typically used for sterilization validation?
Depending on the sterilization method, the following standards apply:
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ISO 11135 – Ethylene oxide (EtO) sterilization
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ISO 11137 – Radiation sterilization (gamma, electron beam, X-ray)
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ISO 17665 – Moist heat (steam) sterilization
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ISO 20857 – Dry heat sterilization
What documents are required to demonstrate sterilization validation?
Required documents include:
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Validation protocol and report (covering IQ, OQ, PQ)
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Sterilizer calibration and maintenance records
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Biological indicator (BI) and chemical indicator (CI) test results
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Batch records showing process parameters met specifications
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Revalidation and change control documentation
When should revalidation of the sterilization process be performed?
Revalidation is required when there are:
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Changes in device design, packaging, or materials
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Changes in sterilizer equipment or location
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Modifications in cycle parameters or load configuration
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Deviations or out-of-specification results during monitoring