The chip, developed by US tech company Digital Angel Corporation and known as VeriChip, is currently used in tagging pets and livestock, but following Wednesday's decision by the FDA, the device can now be used in the US by humans.
According to Applied Digital Solutions, the parent company of Digital Angel, and licensee of the VeriChip technology, the chip is about the size of a grain of rice, and is the world's first "subdermal, radio frequency identification (RFID) microchip".
An RFID chip comprises a microchip and a tiny antenna that transmits the data from the chip to a reader. The reader is activated whenever the antenna comes into range and the data can be used to trigger an event – such as raising an alarm. Usually the range is no more than a few feet.
ADS hopes to use VeriChip to create a medical records system that will reduce the number of errors caused by problems in identifying the patient, or where important medical information, such as an allergy warning, is not immediately available.
The chip, says ADS, will be injected under the patient's skin, typically somewhere between the elbow and shoulder, in a brief outpatient procedure.
It will contain a unique 16-digit verification number that can be captured by briefly passing a proprietary scanner over the insertion site. The captured 16-digit number then links to a medical records database via encrypted internet access and the previously stored information is then conveyed via the internet to the registered requesting healthcare provider.
But privacy activists have expressed concern about the chip, which they say could allow for the surveillance of patients.
"If privacy protections aren't built in at the outset, there could be harmful consequences for patients," Emily Stewart, a policy analyst at the rights group the Health Privacy Project, told the Associated Press.
"It would obviously be possible to inject one of these into everyone," Katherine Albrecht, Founder and Director of anti-RFID group Consumers Against Supermarket Privacy Invasion and Numbering (CASPIAN), told the Washington Post. "In the post-9/11 world, we are already racing down the path to total surveillance. The only thing missing to clinch the deal has been the technology. This may fill that gap."