Health-care researchers estimate that doctors make five to eight wrong-site surgeries--the wrong leg or the wrong procedure--each month. Exceedingly rare, but enough to worry anyone facing surgery.

New radio-frequency identification technology approved by the Food and Drug Administration in November is starting to be used to address that problem. The new RFID verification system, called Surgichip, is being sold by AMTSystems as part of its suite of PatientSafe patient-safety systems, which also include medication-verification products.

Surgichip is an RFID tag that gets encoded by medical staff with a patient's name and other identification such as date of birth and medical-record number, as well as information about the type and site of procedure and other surgical instructions.

The 2-by-1-inch label gets stuck to a patient's skin near the surgical site, such as a left knee, before the operation. Before surgery begins, the tags are read by operating-room staff with handheld readers to confirm the patient and procedure.

"This is one more way for us to be supersure" that the correct patient is about to undergo the right surgery, says Dr. Frank Cook, an orthopedic surgeon at the Palm Beach Orthopedic Institution, whose doctors have tested the system for about a year in some 300 surgical procedures.

Using Surgichip costs about $6 to $9 per surgery, including the costs of software installation, in the first year.