When this test applies
ISO 10993-1:2025 flags implantation effects for devices with prolonged or long-term contact with tissue, bone or blood, and for implants. The intramuscular or subcutaneous route is the general soft-tissue model and the default for most implants and prolonged-contact devices. The 26-week duration is chosen to match the contact duration and the expected healing timeline; ISO 10993-6 expects the study period to be long enough for a steady-state tissue response.
When to run it
Late, and only once the material, surface finish, sterilisation and manufacturing process are locked — the study follows the implant for 26 weeks and cannot be shortened or repeated cheaply. Cytotoxicity, sensitization and irritation should be clear first. Confirm the implantation period and route in a biological evaluation plan before commissioning: for a permanent implant more than one period is often expected, and bone implantation may also be needed if the device contacts both.
What a pass tells you
That the test sites, scored histologically against the control sites per ISO 10993-6 Annex E, gave an irritation ranking in the non-irritant range — a difference of 2.9 or less. The score covers inflammatory cell infiltrate, neovascularisation, fibrosis and fatty infiltrate, after 26 weeks of implantation.
What it does not tell you
A clear result at 26 weeks says nothing about longer durations; a permanent implant will usually need a longer period as well. It does not address systemic toxicity, genotoxicity, sensitization or hemocompatibility, each of which is its own endpoint, and the soft-tissue route does not stand in for the other.
Method
Testing per ISO 10993-6:2016. Solid test samples, prepared to the dimensions in the standard (1 mm × 10 mm), and control samples are implanted intramuscularly or subcutaneously in the rabbit. After the 26 weeks implantation period the sites are explanted, examined macroscopically, processed for histology and scored by a pathologist against the control sites; the difference is expressed as an irritation ranking per Annex E. No extraction is involved — the material itself is tested.
Where it runs
This method is internationally sourced (OUS). The laboratory is ISO/IEC 17025 accredited and GLP certified, and the report is issued under Groenakker’s ISO 13485:2016 certified quality system, in Groenakker’s report template or in your document template on request at no extra cost.
Usually ordered alongside
The other implantation periods for the same route where a permanent implant calls for more than one, bone implantation where the device contacts both tissue types, and 28-day systemic toxicity where long-term contact also opens that endpoint. Cytotoxicity should already be clear.
