Classes A, B, C and D — Classification Rules
Overview of classification factors
Singapore's classification rules, set out in the HP(MD) Regulations 2010, assess devices across several key dimensions. Understanding these dimensions helps predict and verify classification.
1. Invasiveness
| Category | Definition |
|---|---|
| Non-invasive | Does not enter the body through a body orifice or through the skin |
| Invasive — body orifice | Enters the body through a natural body orifice (e.g. mouth, ear, nose, vagina, urethra, anus) |
| Invasive — surgically | Enters the body through a surgical incision or puncture in the skin |
| Implantable | Intended to be wholly or partially inserted into the body and to remain there for 30 days or more |
2. Duration of contact
| Duration | Definition |
|---|---|
| Transient | Intended to be used continuously for less than 60 minutes |
| Short-term | Intended to be used continuously for 60 minutes to 30 days |
| Long-term | Intended to be used continuously for more than 30 days |
3. Active vs non-active
An active medical device is one that depends on a source of energy (electrical, thermal, ionising radiation, etc.) other than that generated by the human body or gravity to achieve its principal intended action.
Class A — the baseline
Class A captures non-invasive devices where no special characteristics apply that would push them to a higher class. General principles:
- Non-invasive devices that have no contact with the patient, or contact only intact skin, and do not absorb substances or contact wounds — typically Class A.
- Devices intended to be used as a channel or storage for blood, body liquids, tissues, cells, organs, or other biological material — potentially Class A unless they interact with or introduce biological substances.
Class A examples:
- Bandages and sticking plasters (non-sterile)
- Patient weighing scales, measuring equipment
- Non-powered wheelchairs and walking aids
- Eyeglasses frames (no lenses)
- Hospital bed mattresses
- Tongue depressors, spatulas
Class B — elevated risk
Class B captures devices with moderate invasiveness or specific active functions. General indicators include:
- Invasive devices (body-orifice) intended for transient use;
- Non-invasive devices in contact with broken skin or a wound;
- Active devices intended to supply or exchange energy;
- Active devices intended to diagnose, monitor, or control via active means (but not high-energy therapeutic devices).
Class B examples:
- Hypodermic needles and syringes
- Sterile wound dressings
- Nasal catheters
- Dental hand instruments
- Corrective contact lenses (non-active)
- Basic IVDs for self-testing (low-risk analytes)
- Physiotherapy laser equipment (low power)
Class C — high risk
Class C captures devices where longer-term invasiveness, or use in critical or complex physiological functions is involved.
General indicators include:
- Long-term invasive surgical devices intended to contact the heart, circulatory system, or central nervous system;
- Active devices intended to deliver energy to the patient (e.g. ventilators, infusion pumps, external pacemakers);
- Devices incorporating a biological substance that acts in an ancillary manner;
- IVDs for HIV testing (blood donors), blood compatibility testing, and certain infectious disease screening.
Class C examples:
- Ventilators and anaesthesia delivery equipment
- Haemodialysis machines
- Long-term non-bioactive implants (hip, knee, shoulder — non-bioactive)
- Infusion pumps
- Blood bags
- Diagnostic HIV IVDs (general screening)
Class D — highest risk
Class D covers devices with the highest inherent risk, including active implantable devices and devices where malfunction would immediately result in serious harm or death.
General indicators include:
- Active implantable devices (devices powered by an energy source and intended to be wholly or partially implanted, e.g. pacemakers, neurostimulators, cochlear implants);
- Devices intended to contact the central circulatory system or central nervous system on a long-term basis;
- Bioactive implants (hip, knee, shoulder with bioactive coating or material);
- Drug–device combinations where a registrable drug plays a secondary role;
- Specific high-risk IVDs (blood/tissue donor compatibility tests, HIV screening).
Class D examples:
- Cardiac pacemakers and defibrillators
- Cochlear implants
- Neurostimulators
- Drug-eluting stents
- Bioactive spinal implants
- HIV blood donor screening IVDs
Devices excluded from expedited routes
Certain Class C and Class D devices cannot use the Expedited Class C (ECR) or Expedited Class D (EDR) routes, regardless of overseas approvals. They must use Full or Abridged evaluation:
Class C — ECR excluded:
- Hip, knee, and shoulder joint replacement non-bioactive implants (metal/polymer)
Class D — EDR excluded:
- Active implantable devices (pacemakers, neurostimulators)
- Implantable devices in contact with the central circulatory system or CNS
- Hip, knee, and shoulder joint replacements (bioactive implants)
- Devices with a registrable drug in a secondary role
- IVD assays for HIV testing and blood/tissue donor compatibility testing (excluding IVD analysers)
Official sources
- HSA: Risk classification rules and factors
- HSA: Risk classification tool
- HP(MD) Regulations 2010 — Schedule 1
Class D — highest risk
Class D covers devices with the highest inherent risk, including active implantable devices and devices where malfunction would immediately result in serious harm or death.
General indicators include: Active implantable devices (devices powered by an energy source and intended to be wholly or partially implanted, e.g. pacemakers, neurostimulators, cochlear implants); Devices intended to contact the central circulatory system or central nervous system on a long-term basis; Devices intended to administer medicinal products by a potentially hazardous route or in a manner where there is a direct physiological link to a dangerous situation; Devices that incorporate a drug that is itself a registrable therapeutic product and the drug is the primary component; All active implantable IVDs and Class D IVDs (e.g. blood donor compatibility testing, blood products screening).
Class D examples: Pacemakers and neurostimulators Cochlear implants Implantable cardioverter-defibrillators (ICDs) Drug-eluting stents (where the drug is primary) Blood donor compatibility testing IVDs Blood products screening IVDs