How a Selected Radiation Dose Is Substantiated Under ISO 13004
Radiation sterilization suits single-use items because the product can be processed after it is sealed in its final packaging. The open question has always been the dose. For years a common answer was 25 kGy, chosen by convention. ISO 13004 describes how a preselected dose is substantiated with evidence rather than assumption.
What the method does
ISO 13004 sets out a method for substantiating a selected sterilization dose, referred to as VDmaxSD. Rather than running a full dose-setting experiment, the method starts from a preselected dose and defines the microbiological work needed to show that the dose achieves the required sterility assurance level for that product family. The output is a documented justification, not a label claim.
Where it fits with the rest of the series
- ISO 11137-1: requirements for radiation sterilization development, validation and routine control
- ISO 11137-2: dose-setting methods, including Method 1 and VDmax25
- ISO 13004: substantiation of a selected dose, VDmaxSD
- ISO 11737-1 and -2: bioburden estimation and sterility testing
Read together, these documents connect a number on a specification sheet to the laboratory work behind it.
What sits behind the dose
| Document | What it records | Why a buyer cares |
|---|---|---|
| :-- | :-- | :-- |
| Bioburden study | Counts and types of organisms on the product | Sets the starting point for the dose argument |
| Dose substantiation report | How the selected dose was justified | The core evidence for the claim |
| Dose audit record | Periodic re-verification of the dose | Shows the argument is still current |
| Processing certificate | Which lot was treated and how | Lot-level traceability |
How this affects a purchasing file
A sterile claim is a chain, not a sentence. Supplier qualification, packaging validation, dose substantiation and dose audits are the links. When a clinic buys sterile single-use items such as gauze, swabs or specimen bags, the items arrive sterile because that chain holds, and the paperwork is how a buyer checks it without visiting the plant.
Practical questions for the next tender
Ask which method was used to set or substantiate the dose, when the last dose audit was completed, and what happens if an audit fails. Ask also whether the product family used to substantiate the dose includes the exact item being purchased, because dose arguments are written for families, not for individual SKUs.
For sterile single-use supplies, sterile gauze sponges (gauze sponges, sterile 12-ply) and 95 kPa specimen transport bags (UN3373 specimen bags, 12 by 15 inch) are typical items where the dose argument matters. Labs that verify cycles in house use biological indicators (24-hour self-contained BIs, 50-pack), and a smaller starting quantity is available through the biological indicator 5-pack trial at CA $12.99 with shipping included.
References
- ISO 13004 - Substantiation of selected sterilization dose, method VDmaxSD (checked 20 September 2026)
- Health Canada - Medical devices (checked 20 September 2026)
Related Reading
- Laboratory consumables
- Learning Hub - clinical and procurement guides
- Wholesale and multi-site ordering
- ISO 11137-2: how a radiation sterilization dose is set
- ISO 11737-1 and -2: bioburden and sterility testing explained
- free Ontario sterilization compliance log
- printable autoclave sterilization log sheet (free)
Frequently Asked Questions
What does ISO 13004 cover?
It describes a method for substantiating a selected radiation sterilization dose, known as VDmaxSD. Instead of calculating a dose from scratch, the method takes a preselected dose and sets out the testing needed to justify it for a defined product family.
How is it different from ISO 11137-2?
ISO 11137-2 contains the dose-setting methods, including Method 1, which calculates a dose from bioburden data. ISO 13004 addresses the case where a preselected dose is used and has to be substantiated with documented microbiological evidence.
Why does the 25 kGy figure keep appearing?
It has been used as a common preselected dose for many single-use products and still works as a starting point in some methods. The point of the newer approach is that the dose is backed by product-specific data rather than by convention.
What can a buyer ask for?
Ask for the dose substantiation report, the bioburden data behind it and the dose audit history. The audit is the part that shows the dose is still justified after a year or two of production.
Last updated: September 2026. CliniEco Medical holds MDEL #35334 issued by Health Canada, and supplies clinics, long-term care homes and home-care programs across Canada.
0 commentaire