Glossary

Biocompatibility

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Biocompatibility is a device’s ability to perform its intended function, in contact with the body,
without causing unacceptable biological risk to the patient or user. Manufacturers demonstrate
biocompatibility using a risk-based approach aligned with the nature and duration of body contact, supported by
material characterization, toxicological assessment, and biological testing where needed.

Risk-based
Contact type & duration
ISO 10993 series

What biocompatibility covers

  • Contact categorization: surface, external communicating (e.g., blood path), or implant; and duration (limited <24h, prolonged 24h–30d, permanent >30d).
  • Material & chemical characterization: composition, processing aids/residues, extractables/leachables, degradation products.
  • Biological endpoints (as applicable): cytotoxicity, sensitization, irritation/intracutaneous reactivity, acute/sub-chronic/chronic systemic toxicity, genotoxicity, implantation, hemocompatibility, reproduction & developmental toxicity, carcinogenicity.
  • Toxicological risk assessment: integrate chemistry and exposure to judge margin of safety for users/patients.

Process — practical steps

1) Define contact & use
State intended purpose, user/population, tissues/fluids contacted, and total contact duration; this drives endpoint selection.
2) Characterize materials & chemistry
Document formulation and manufacturing; perform chemical characterization (including extractables/leachables) when relevant to support tox assessment.
3) Map endpoints & justify strategy
Use contact/duration to select biological endpoints; justify any not applicable items; leverage prior data where scientifically valid.
4) Generate evidence
Perform testing per recognized methods when needed (e.g., cytotoxicity, sensitization, irritation, hemocompatibility, implantation); use validated labs/methods.
5) Toxicological risk assessment
Evaluate exposure to identified chemicals vs. health-based limits; conclude acceptability with uncertainty clearly addressed.
6) Conclude & maintain
Document rationale and results in the biological evaluation report; update with changes (materials, process, sterilization) and post-market information.

Common pitfalls

  • Testing without a prior risk-based strategy or contact/duration mapping.
  • Insufficient chemical characterization to support a toxicological assessment.
  • Poor sample preparation (non-representative worst-case) leading to inconclusive results.
  • Missing justification for not applicable biological endpoints.
  • Not updating evidence after changes (materials, suppliers, sterilization, processing aids).

Quick checklist

  • Contact type and duration correctly classified; endpoints mapped and justified.
  • Material and chemical characterization complete and relevant to exposure.
  • Testing performed only where needed, with validated methods and representative samples.
  • Toxicological risk assessment supports acceptable biological safety margins.
  • Documentation is traceable in the technical file and kept current post-market.

Biocompatibility — FAQs

Is biocompatibility always proven by testing?
No. A risk-based approach may rely on chemical characterization, literature, prior data, and toxicological assessment; testing is performed when needed to close evidence gaps.
How do contact duration and type affect requirements?
They determine which biological endpoints are relevant and the depth of evidence required; longer or more invasive contact typically demands more endpoints and data.
When must evidence be updated?
After design/material/process/sterilization changes, when new hazards emerge, or when PMS/PMCF indicates new risks; re-evaluate chemical and biological profiles accordingly.