Some doctors are welcoming VeriChip technology as an exciting innovation that will speed care and prevent errors.

Emergency-room doctors could scan unconscious or incoherent patients to quickly check their blood type and find out if they are taking any medications or have allergies or other medical conditions. Nurses could identify family members and determine whether patients are organ donors or have living wills. Surgeons could scan patients on the operating table to make sure they are working on the right person.

But the concept alarms privacy advocates. They worry the devices could make it easier for unauthorized snoops to invade medical records. They also fear that the technology marks a dangerous step toward an Orwellian future in which people will be monitored using the chips or will be required to have them inserted for surveillance.