Gap Assessment: ISO 11137-1:2025 vs ISO 11137-1:2006

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Regulatory Specialist

Fri May 09 2025•5 min read

What’s Changed and How It Affects Your Radiation Sterilization Program

With the release of ISO 11137-1:2025, significant updates have been made to align with current technological advances and best practices in radiation sterilization — especially for gamma, electron beam, and X-ray methods. This document provides a gap analysis comparing the new revision against ISO 11137-1:2006, highlighting critical changes you need to address in your Quality and Sterilization Management Systems.

Key Changes & Gap Assessment

#1. New Normative Reference: ISO 13004:2022 The 2025 revision now includes ISO 13004:2022: Sterilization of health care products — Radiation — Substantiation of selected sterilization dose: Method VDmaxSD.

Impact: Organizations using the VDmaxSD method for dose substantiation must now comply with the procedural and documentation requirements set forth in ISO 13004. This impacts validation documentation, training, and internal procedures.

Action Required:

Integrate ISO 13004 compliance into your radiation dose substantiation protocols.
Update SOPs and training materials.

2. Increased Energy Thresholds for Induced Radioactivity Assessment

Old (2006): If the energy level for electrons exceeds 10 MeV or for X-rays exceeds 5 MeV, assess potential for induced radioactivity.

New (2025): Thresholds increased to 11 MeV (electrons) and 7.5 MeV (X-rays).

Impact: More flexibility is now allowed before a radioactivity assessment is mandatory.

Action Required:

Re-evaluate your equipment's energy output.
Ensure assessments are documented if new thresholds are exceeded.

3. Enhanced Monitoring Requirements in Process Characterization (Clause 6.1)

Systems must now ensure that failure in control functions does not lead to failure in monitoring, which could falsely indicate an effective process.

Acceptable Approaches:

Independent Monitoring Systems
Cross-Check Mechanisms

Non-compliant Scenario: Only recording irradiator setpoints without independent dose verification.

Action Required:

Implement or validate redundancy in monitoring systems.
Review equipment design and ensure independent or cross-checked verification.

4. Detailed clarification: Equipment Design Specification (Clause 6.2.3)

You must now formally define and document the design specification of sterilization equipment. In the previous version, the specifications were presented in a general format. In this updated version, the requirements have been organized and detailed in a tabular format for better clarity and structure.

Action Required:

Ensure documentation includes control systems, monitoring tools, and fail-safes.
Update Installations qualification protocols.

5. Clarified Guidance: Transference of Verification and Sterilization Doses (Clause 8.4.2)

Separate guidance is provided for dose transference based on whether water is present in liquid or non-liquid form.

Action Required:

If the product contains material in a liquid state, verify the operating conditions of both radiation sources to ensure they do not impact the microbicidal effectiveness.
Update dose verification protocols accordingly.

6. Bioburden Testing Frequency Update (Clause 12.1.2)

Old Standard:

ISO 11137-1:2006	ISO 11137-1:2025
Case 1: For product of average bioburden ≥ 1.5, the maximum interval of time between determinations of bioburden shall be three months.	Bioburden determination shall be performed at least four times per year, with the interval not exceeding four months from the previous sampling.
Case 2: For product of average bioburden < 1.5 and for which a) the sterilization dose has been set using Method 2, or b) a sterilization dose of 25 kGy has been selected, the maximum interval of time between determinations of bioburden shall be three months.	–
Case 3: For product of average bioburden < 1.5 and for which a) the sterilization dose has been set using Method 1, or b) a sterilization dose of 15 kGy has been selected, the maximum interval of time between determinations of bioburden shall be one month.	–

Action Required:

Review product testing schedules.

7. Dose Mapping Replication Requirement (Clause 9.2.5: OQ)

What’s new? At least three replicate dose mappings are required during Operational Qualification (OQ).

Action Required:

Ensure all dose mapping validations include three independent runs.
Review and potentially revalidate existing OQ records.

Summary of Key Action Points

Ready for the Next Step?

Whether you are currently utilizing radiation sterilization or exploring it as an alternative to ethylene oxide (EO) or steam, V-REG Solutions is equipped to support your transition to ISO 11137-1:2025 with tailored, expert-driven solutions: