How do Pet Microchips Work?

The technology of a pet microchip is simple and safe.

The brilliance of a microchip implant is its simplicity.

No bigger than a grain of rice, a pet microchip is a radio-frequency identification transponder made up of just a few components encased within a slender capsule of bioglass, which is used extensively for implants in both humans and animals.Some microchips have anti-migration features to ensure capsules stay in place by bonding with the tissue under the animal's skin.

• A microchip's sole function is to store a unique ID number that is used to retrieve a pet parent's contact information—it differs from a Global Positioning System, which is used for tracking, and requires a power source such as a battery.

• When a microchip scanner is passed over the skin of a microchipped pet, the implanted microchip emits an RF (radio frequency) signal.The scanner reads the microchip's unique ID code.The microchip registry is called, and the registry company uses the ID number to retrieve the pet parent's contact information from the pet recovery database.

• Most animal shelters and veterinary hospitals in the U.S.have global scanners that read pet microchips from most manufacturers.

Microchips have different frequencies.

Microchips are passive devices, which means they have no internal energy source.They stay dormant until they are activated by a scanner.In the U.S., several different microchip frequencies have been used for pet microchips:

• The 125kHz chip – until recently, this was the most common frequency in the U.S., and can be read by most scanners in the U.S.

• The 134kHz chip – was introduced to the U.S.in 2004.This microchip is defined by specifications developed by the International Standards Organization or commonly known as ISO.The microchip ID code format for this chip is defined as a 15-digit numeric code that uses 0-9, where the first three digits represent a country code or a manufacturers code.This frequently is considered the "global standard" for pet microchips, as it is used by the rest of the pet microchipping world.

• The 128 kHz chip – introduced in 2007, can be read by many scanners, but not all.

Does the frequency matter?Yes and No.

• Virtually all shelters and veterinary clinics have scanners.It is estimated that by early 2008, there were already over 70,000 "universal scanners" in the U.S.—scanners that read all frequencies of microchips ever sold here, including the new ISO standard.

• Many leaders in animal health recommend the new ISO standard, including American Veterinary Medical Association and the American Animal Hospital Association.

• If you travel outside of the United States with your pet, it is likely that your pet will need a microchip to enter the foreign country.If so, have your pet implanted with an ISO chip, since most countries outside the United States use the ISO standard and their scanners will not read the other frequencies.If your pet has already been implanted with a different frequency, some countries will allow you to bring your pet as long as you bring a microchip scanner with you that can read the ID number.

Do not microchip your pet again, as multiple microchips can interfere with accurate readings.

• You should ask your veterinarian which microchip frequency their clinic recommends.