When this test applies
Required for implanted devices and for devices contacting breached or compromised tissue, under ISO 10993-1:2025. The intramuscular or subcutaneous route represents soft-tissue contact; devices contacting bone are assessed by the bone route instead. The 4-week timepoint sits between the acute reaction and its resolution: it shows whether the early response is subsiding on schedule or persisting.
When to run it
Late, and only once the material and its manufacturing process are locked. Implantation is the longest and most expensive study in the battery, and a formulation change after the implants go in means starting over. Your biological evaluation plan should settle which timepoints the device category actually requires before any of them are commissioned.
What a pass tells you
That the histological response at the test sites, scored against the control sites per ISO 10993-6 Annex E, produced an irritation ranking of 2.9 or less — classed as a non-irritant over a 4 weeks implantation period by this route.
What it does not tell you
Nothing about the response at a different timepoint or by a different route. A 4-week result does not predict the 13- or 26-week outcome; a response that is resolving at four weeks can still leave a chronic picture at six months. It also says nothing about systemic effects, genotoxicity or sensitization, each of which is a separate endpoint.
Method
Testing per ISO 10993-6:2016 in the rabbit. Solid samples are implanted directly — there is no extraction step — with sample geometry prepared to the dimensions ISO 10993-6 specifies for the intramuscular or subcutaneous route. After the 4 weeks implantation period the test and control sites are explanted, processed histologically and reviewed by a pathologist, and scored to derive an irritation ranking per Annex E.
Where it runs
This method is internationally sourced. The laboratory is ISO/IEC 17025 accredited and GLP certified, and the report is issued under Groenakker cover, in Groenakker’s report template or in your document template on request at no extra cost.
Usually ordered alongside
Cytotoxicity, sensitization and irritation as the baseline battery, and usually another timepoint in the same programme. Where the device contacts bone, the bone-route studies apply instead of, or in addition to, these.
