Classification of medical devices based on the risk involved is an important step in medical device approval process. While the medical devices are classified into 3 categories in the US, they are classified into 4 categories in the European Union (EU).
1. FDA Medical Device Classification
FDA 21 CFR Part 860 classifies devices based on their potential risks.
- Class I devices are simple to manufacture and have less regulatory hurdles for clearance. These devices are subjected to general controls like adulteration and misbranding.
- Class II devices are riskier and require FDA 510 (k) clearance. Examples of class II devices are X-ray machines, insulin pumps, condoms, and surgical drapes.
- Class III devices are the riskiest of all and include devices like a stent, artificial heart valves, and breast implants. These devices require Pre Market Approval (PMA) as well as 510(k) clearance before commercial release.
2. EU MDR Classification of Medical Devices
According to the Chapter III of EU MDR, all medical devices can be classified into Class I, Class IIa, Class IIb or Class III devices. Here are the two major parameters which determine the device classification.
- Energy activity
- Duration of contact with body
2.1. Class I Medical Devices
Non-invasive devices are classified as Class I medical device. Class I devices which require CE marking can be further classified as Class Is, Class Ir, Class Im. All those devices which are don’t fall into either of Class Is, Im or Ir don’t require CE marking.
- Class Ir or Class I Reusable Devices: These are reusable surgical instruments. Examples include endoscopes, forceps and surgical scissors. From 2020 onwards, all the Class Ir medical devices should have a CE mark before being launched in the market.
- Class Is or Sterile Devices: Examples include a stethoscope, examination gloves, and oxygen masks.
- Class Im or Devices with measuring function: These are low risk measuring devices. These medical devices need to be compliant with metrological requirements. Examples are thermometer, droppers and non-invasive blood pressure monitoring devices.
2.2. Class IIa Medical Devices
These are low to medium risk devices which can be installed in the body between 1 hour to 30 days. Examples include hearing aids, exoskeletons and catheters.
However, it is to be noted that catheters used in balloon angioplasty are classified as class III medical devices.
Surgically invasive devices with transient use like needles used for suturing, lancets and staplers are classified as Class IIa medical devices. However, epidural needles which come into contact with the spinal cord and Central Nervous System (CNS) is classified as Class III medical device.
Software for monitoring physiological processes are classified as Class IIa medical devices. However, if there is a software that monitors a vital function and an error in measurement could lead to taking a decision which results in patient’s death, the software is classified as Class IIB medical device.
These devices need conformity tests and technical file submission to the regulatory body.
2.3. Class IIb Medical Devices
They are installed within the body for 30 days or longer. All surgically invasive devices meant to administer medicines are classified as Class IIb.
Usually medical devices for storage of biological fluids are classified as Class IIa. However, blood bags are an exception and classified as Class IIb.