Overview
ISO 10993-5:2009, "Biological evaluation of medical devices - Part 5: Tests for in vitro cytotoxicity," specifies methods to assess the in vitro cytotoxicity of medical devices and materials. The standard defines extract, direct-contact and indirect-contact test approaches in which cultured mammalian cells are incubated with devices or device extracts to determine cellular responses using appropriate biological endpoints. ISO 10993-5 is part of the ISO 10993 series for biological evaluation of medical devices.
Key topics and technical requirements
- Test categories:
- Extract tests (expose cells to liquid extracts of the device)
- Direct-contact tests (device placed directly onto cell monolayer)
- Indirect-contact tests (diffusion-based exposure)
- Sample and control preparation:
- Sample preparation per ISO 10993-12; include negative, positive and blank controls in each assay. Examples in the standard include organotin‑stabilized polyurethane or phenol as positive controls and high‑density polyethylene as a negative control.
- Extraction vehicles and conditions:
- Preferred vehicle: culture medium with serum; other vehicles (saline, purified water, DMSO) may be used with justification.
- Typical extraction conditions (historical precedent): 24 ±2 h at 37 ±1 °C; 72 ±2 h at 50 ±2 °C; 24 ±2 h at 70 ±2 °C; or 1 ±0.2 h at 121 ±2 °C - choice depends on device characteristics and intended use.
- Cell systems and media: selection of appropriate cell lines and culture media; maintain subconfluent cultures for exposure.
- Endpoints and evaluation methods: morphological assessment, measures of cell damage, cell growth/clonogenic assays, and metabolic assays. Informative annexes provide example protocols (e.g., Neutral Red Uptake, colony formation, MTT, XTT).
- Reporting and result interpretation: requirements for test reports and guidance on assessing cytotoxic effects.
Applications and who uses it
ISO 10993-5 is used by:
- Medical device manufacturers for preclinical biocompatibility screening and material selection
- Contract testing laboratories performing cytotoxicity assays
- Regulatory and quality assurance teams preparing submissions and risk assessments
- R&D and toxicology scientists evaluating new materials, coatings or sterilization effects
Practical uses include screening raw materials, evaluating finished device extracts, verifying sterilization/processing effects, and providing evidence for regulatory dossiers.
Related standards
- ISO 10993-1: Evaluation and testing within a risk management process (normative reference)
- ISO 10993-12: Sample preparation and reference materials (normative reference)
- Other parts of ISO 10993 (e.g., Parts 6, 7, 10, 11) provide complementary guidance on implantation, sterilization residuals, irritation, and systemic toxicity.
Keywords: ISO 10993-5:2009, in vitro cytotoxicity, cytotoxicity testing, medical devices, biological evaluation, extract test, direct contact, indirect contact, MTT, NRU, XTT.
Open preview (PDF)Biological evaluation of medical devices — Part 5: Tests for in vitro cytotoxicity
