As of November 1, 1995, Medicare contractors may provide benefits for devices that are not approved for marketing by the Food and Drug Administration (FDA). See 42 CFR Part 405, Subpart B.

If a device still in clinical trials has been granted an Investigational Device Exemption (IDE) by the FDA, it is eligible for Medicare reimbursement if the device is deemed by the FDA to be not truly investigational or experimental, as underlying questions of safety or effectiveness have previously been resolved. The FDA assigns these devices to "Category B".

Any Medicare carrier or intermediary is granted discretion to cover "Category B" devices, so long as coverage is not prohibited by other HCFA coverage requirements. Devices that currently fall into this category included the auditory brainstem implant (ABI), or new generation versions of cochlear implants still in clinical trials.