PMA requirements apply to Class III preamendment devices, transitional devices, and postamendment devices.
A preamendments device is one that was in commercial distribution before May 28, 1976, the date the Medical Device Amendments were signed into law. After the Medical Device Amendments became law, the classification of devices was determined by FDA classification panels. Eventually all Class III devices will require a PMA. However, preamendment Class III devices require a PMA only after FDA publishes a regulation calling for PMA submissions. The preamendment devices must have a PMA filed for the device by the effective date published in the regulation in order to continue marketing the device. The CFR will state the date that a PMA is required. Prior to the PMA effective date, the devices must have a cleared Premarket Notification 510(k) prior to marketing. Class III Preamendment devices that require a 510(k) are identified in the CFR as Class III and include the statement "Date premarket approval application (PMA) or notice of completion of product development protocol (PDP) is required. No effective date has been established of the requirement for premarket approval." Examples include intra-aortic balloon and control system (21 CFR 870. 3535), ventricular bypass (assist) device (21 CFR 870.3545), cardiovascular permanent pacemaker electrode (21 CFR 870.3680), and topical oxygen chamber for extremities (21 CFR 878.5650).
A postamendment device is one that was first distributed commercially on or after May 28, 1976. Postamendment devices equivalent to preamendment Class III devices are subject to the same requirements as the preamendment devices.
Transitional devices are devices that were regulated by FDA as new drugs before May 28, 1976. Any Class III device that was approved by a New Drug Application (NDA) is now governed by the PMA regulations. The approval numbers for these devices begin with the letter N. These devices are identified in the CFR as Class III devices and state that an approval under section 515 of the Act (PMA) is required as of May 28, 1976 before this device may be commercially distributed. An example of such device is intraocular lenses (21 CFR 886.3600). Please note that some of the transitional devices have been subsequently downclassified to Class II.