The US Food and Drug Administration has approved Verichip, an implantable radiofrequency identification device for patients, which would enable doctors to access their medical records.

Doctors hope that use of the device will result in be better treatment for patients in emergencies or when a patient is unconscious or lacks medical records. Some people have raised fears, however, that it could lead to infringements of patients' privacy.

The chip is the size of a grain of rice and is implanted under local anaesthesia beneath the patient's skin in the triceps area of the right arm, where it is invisible to the naked eye. It contains …