Class I: General Controls
Class I devices present minimal potential for harm to the user and are often simpler in design than Class II or Class III devices. These devices are subject only to general controls. General controls cover such issues as manufacturer registration with the FDA, good manufacturing techniques, proper branding and labelling, notification of the FDA before marketing the device, and general reporting procedures.[2] (Most Class I devices are exempt from the good manufacturing practices and/or the FDA notification regulations.)[2] These controls are deemed sufficient to provide reasonable assurance of the safety and effectiveness of the device; or the device is not life-supporting or life-sustaining and does not present a reasonable source of injury through normal usage. Devices in this category include tongue depressors, bedpans, elastic bandages, most hand-held dental instruments, examination gloves, and hand-held surgical instruments and other similar types of common equipment. Depending on the "stated/purported use" of a device, it may be necessary to obtain a Premarket Approval or 510K for the device, which is otherwise classifiable as a Class 1 device. Such devices are referred to as "reserved devices". The electrically powered arthroscope (which is really an endoscope powered electrically) is a case in point. While endoscopes are Class 1 devices, the electrically powered arthroscopes need a pre-market notification (510K) although the manual arthroscopes do not. Pre-market notified devices are marketed as "at least as safe and effective, that is, substantially equivalent, to a legally marketed device."
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Class II: General Controls with Special Controls
Class II devices are those for which general controls alone are insufficient to assure safety and effectiveness, and additional existing methods are available to provide such assurances. Therefore, Class II devices are also subject to special controls in addition to the general controls of Class I devices. Special controls may include special labeling requirements, mandatory performance standards, and postmarket surveillance.[2] Devices in Class II are held to a higher level of assurance than Class I devices that they will perform as indicated and will not cause injury or harm to patient or user. Devices in this class are typically non-invasive and include x-ray machines, PACS, powered wheelchairs, infusion pumps, surgical drapes, surgical needles and suture material,acupuncture needles.
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Class III: General Controls and Premarket Approval
A Class III device is one for which insufficient information exists to assure safety and effectiveness solely through the general or special controls sufficient for Class I or Class II devices. Such a device needs premarket approval, a scientific review to ensure the device's safety and effectiveness, in addition to the general controls of Class I. Class III devices are described as those for which "insufficient information exists to determine that general controls are sufficient to provide reasonable assurance of its safety and effectiveness or that application of special controls ... would provide such assurance and if, in addition, the device is life-supporting or life-sustaining, or for a use which is of substantial importance in preventing impairment of human health, or if the device presents a potential unreasonable risk of illness or injury."[3]
Examples of Class III devices which require a premarket approval include replacement heart valves, silicone gel-filled breast implants, implanted cerebral stimulators, implantable pacemaker pulse generators and endosseous (intra-bone) implants (with the exception of root-form endosseous dental implants which were recently reclassified as Class II).