The latest scheme for RFID tags is another medical application for microchips implanted in humans. A St. Paul company says it received a U.S. patent last week for a "glucose-sensing RFID implantable microchip" that could allow diabetics to monitor their blood sugar levels.

The microchip injected under a person's skin has a glucose sensor, a passive transponder and an integrated circuit. It can be scanned with an RFID reader to determine blood sugar levels, avoiding the usual method of pricking a finger to measure a drop of blood.

The maker of the technology calls itself Digital Angel, a company best known for producing electronic tags for pets, fish and livestock. Digital Angel is a subsidiary of Applied Digital, the company that makes the VeriChip, the first FDA-approved human implantable microchip.

While it hails the patented chip as a breakthrough, the company says it has "extensive work" ahead before it can gain FDA approval. Digital Angel says it "foresees expansion beyond the human market" because apparently animals have a diabetes problem, too. Meanwhile, some humans are already experimenting with the chips on their own, while others are increasingly worried about such technology.