Cytotoxicity
Cytotoxicity is a biological endpoint in material safety evaluation that describes the damaging effect on living cells. Within the ISO 10993 standard series, ISO 10993-5 (Tests on Cytotoxicity) is the governing test standard.
Test methods per ISO 10993-5:
- Extract method: material extracts are added to cell cultures; cell morphology, viability, and growth inhibition are assessed
- Direct contact method: material sample is placed directly on a cell culture
- Indirect contact method (agar overlay): sample placed on an agar layer over a cell culture
Classification:
- Grade 0 (no cytotoxicity): no measurable cell damage
- Grade 1 (slight): very minor cell changes
- Grade 2 (mild): noticeable but reversible cell changes
- Grade 3 (moderate) and Grade 4 (severe): significant to complete cell destruction
For medical single-use gloves under EN 455-3, no cell damage (Grade 0 or 1 depending on specification) is permitted.
Cytotoxicity is distinct from sensitisation (ISO 10993-10) and irritation (ISO 10993-23) - all three are separate biological endpoints.
Frequently asked questions
What does the cytotoxicity test per ISO 10993-5 assess?
The test evaluates whether extracts or contact with a medical device material cause damage to living cells in cell culture. Cell morphology, viability, and growth inhibition are assessed.
What cytotoxicity grades are defined in ISO 10993-5?
Grade 0: no cytotoxicity. Grade 1: slight cell changes. Grade 2: mild but reversible changes. Grade 3: moderate cell destruction. Grade 4: severe to complete cell destruction. Medical devices typically must achieve Grade 0 or 1.
Is cytotoxicity the same as sensitisation?
No. Cytotoxicity (ISO 10993-5) describes direct cell damage caused by the material. Sensitisation (ISO 10993-10) describes an immune system allergic response. Both are separate biological endpoints with distinct test methods.