ISO 18562-4:2024

Overview

ISO 18562-4:2024 - "Biocompatibility evaluation of breathing gas pathways in healthcare applications - Part 4: Tests for leachables in condensate" specifies chemical test methods and acceptance criteria to identify and quantify substances that can leach into liquid condensate forming inside breathing gas pathways of medical devices. The standard supports toxicological risk assessment (per ISO 18562-1:2024) by defining how to collect condensate samples, chemically characterize leachables, calculate exposure doses and apply verifiable acceptance criteria over the device’s expected lifetime and intended processing.

Keywords: ISO 18562-4:2024, biocompatibility, leachables, condensate, breathing gas pathways, toxicological risk assessment, medical devices.

Key technical topics and requirements

• Scope and applicability
  • Applies to gas pathways where humidified gas can reach full saturation, condensate can form and liquid condensate can reach the patient (e.g., ventilators, anaesthesia workstations, humidifiers, nebulizers, oxygen concentrators, masks, tubing, incubator chambers).
  • Excludes contamination originating from external gas sources and biological evaluation of direct-contact surfaces (handled by ISO 10993 series).
  • Does not address contact with drugs or anaesthetic agents (additional testing may be required if intended).
• Stepwise test approach
  • Identification of applicable gas-pathway surfaces and assessment of whether condensate can reach the patient.
  • Sample collection procedures for condensate under simulated or exaggerated use conditions.
  • Chemical characterization of leachables in condensate using appropriate analytical techniques to identify and quantify organic and inorganic substances (including metals).
  • Calculations for tolerable exposure and exposure dose estimates to support toxicological evaluation.
  • Risk assessment framework aligning results with ISO 18562-1 toxicological endpoints.
  • Reporting requirements to document methods, results and justification of acceptability.

Practical applications and who uses this standard

• Medical device manufacturers - to design and validate respiratory devices and accessories for safe use and regulatory submission.
• Regulatory affairs and compliance teams - to demonstrate conformity with biocompatibility and safety expectations.
• R&D and materials engineers - to select materials and processes that minimize leachables.
• Toxicologists and testing laboratories - to perform chemical characterization, exposure calculations and risk assessments.
• Clinical engineers and hospital procurement teams - to evaluate device safety related to condensate-borne contaminants.

Benefits include clearer, auditable test methods, harmonized acceptance criteria and a structured path to toxicological risk assessment for condensate-related hazards.

Related standards

• ISO 18562-1:2024 (evaluation and testing within a risk management process)
• ISO 10993 series (biological evaluation of medical devices)
• ISO 10993-18:2020+AMD1:2022 (chemical characterization)
• ICH Q3D(R2):2022 (elemental impurities guidance)

This standard is essential when assessing breathing gas pathway safety where condensate could convey hazardous water-soluble substances to patients.