Anyone who has ever owned a pet knows how quickly it can become a cherished member of the family. And anyone who has ever lost a pet knows the pain of heartbreak.

According to the National Council on Pet Population Study and Policy, only about 16 percent of dogs and 2 percent of cats find their way back from shelters to their original owners. While traditional pet identification methods are still recommended, they have limitations. Tags can fade, rust, or get scratched, making them impossible to read. Collars can come off or, even worse, get caught on something while your pet is wandering about, causing him physical harm.

Fortunately, there is a relatively new technology available that may give pets a better chance of being reunited with their owners. It is called the microchip identification system, or microchipping.

How microchipping works

With microchipping, a veterinarian uses a hypodermic needle to inject a tiny computer chip containing a unique identification number just under your pet's skin between the shoulder blades. The number on the computer chip is then entered into a national database along with the corresponding contact information for your pet.

If your lost or stolen pet is found, any animal hospital, shelter, or humane society can use a microchip scanner to read the unique ID number contained on the chip. The veterinarian or shelter worker then phones the database or accesses it on a computer and enters the number on the microchip. The database matches the identification number to your name and phone number so that you can be contacted with the location of your pet.

While the price for microchip implantation can vary, it often falls between $25 and $40. Discounted rates may be available upon adoption at animal shelters or if microchipping is done in conjunction with another procedure such as spaying or neutering at a veterinary practice. There is a fee, usually less than $20, to enter your pet's ID number into a database. There is also a nominal fee for changing your contact information if necessary.

Pros

• Microchips are convenient, safe, and reliable.
• Implantation is simple and routine.
• The chip can't be lost or damaged, and it lasts for the pet's lifetime.

Cons

• A microchip won't work unless your pet is properly scanned by a microchip reader. There are some shelters and veterinarians in the United States that don't have readers yet.
• Until recently, each brand of microchip could only be read by its own brand of microchip scanner. (Currently there are two brands of microchips on the market: AVID and HomeAgain.) Not all shelters and veterinarians have the new universal readers.
• Microchip scanning is not 100 percent effective. Microchips should be scanned before being placed in a pet to ensure that the unique identifying number is readable.

To find out more about microchipping, contact your veterinarian or local animal shelter. You can also obtain additional information on the Web:

• Healthy Pet
  
• Save Our Strays
  
• AVID ID
  
• HomeAgain ID

Dr. Jeffrey Proulx is the Director of Veterinary Services for The San Francisco SPCA.