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How Classification Works

Overview​

Classification assigns every medical device to one of four classes — Class I, IIa, IIb, or III — based on risk, invasiveness, and duration of contact. It is the manufacturer's responsibility, applied using MedDO Annex VIII. The class drives the conformity assessment route and Swissmedic registration requirements.

The Four Classes​

ClassRiskExamples
Class ILowBandages, non-sterile surgical instruments, wheelchairs
Class IIaMedium-lowBlood glucose monitors, ultrasound equipment
Class IIbMedium-highVentilators, orthopaedic implants, contraceptive devices
Class IIIHighestDrug-eluting stents, transcatheter heart valves, active implantables

Class I sub-types: Im (measuring function), Is (supplied sterile), Ir (reusable surgical instruments).

The 22 Classification Rules​

MedDO Annex VIII Part II contains 22 rules organised by device type:

  • Rules 1–4: Non-invasive devices
  • Rules 5–8: Invasive devices
  • Rules 9–13: Active devices
  • Rules 14–22: Special rules (software, nanomaterials, combination devices, spinal, etc.)

See MedDO Classification Rules 1–22 for full detail on each rule.

The Highest-Class Rule​

If multiple rules yield different classes, the device is assigned to the highest class. This prevents under-classification of multi-function devices.

Practical Classification Steps​

  1. Define the intended purpose precisely (patient population, body contact, duration, active/non-active)
  2. Work through all 22 rules — flag every rule that could apply
  3. Apply the highest-class rule where multiple rules apply
  4. Document the classification rationale in technical documentation
  5. Review classification whenever intended purpose or design changes significantly; document the rationale for any reclassification. Notification to Swissmedic is required if the device is reclassified to a higher class, as this may trigger conformity assessment route changes and require an updated conformity assessment before continued market placement.; document the rationale for any reclassification. Notification to Swissmedic is required if the device is reclassified to a higher class, as this may trigger conformity assessment route changes and require an updated conformity assessment before continued market placement.