Microchipping Your Dog or Cat

WebMD veterinary expert answers commonly asked questions about microchipping your dog or cat.

By Sandy Eckstein
WebMD Pet Health Feature

Reviewed by Audrey Cook, BVM&S

Up to 8 million animals end up in shelters every year. Unfortunately, only 15-20% of dogs and less than 2% of cats are ever reclaimed by their owners. One of the ways to increase the chances of finding your lost pet is having it microchipped. We asked Louise Murray, director of medicine for the ASPCA's Bergh Memorial Animal Hospital in New York City to explain microchipping.

Q: What is microchipping, and can it be done to any animal?

A: A needle is used to place a little chip under the animal's skin, usually between the shoulder blades. That chip has a unique number on it that can be picked up and read by a scanner.

It can be done to lots of different animals, including horses, dogs, cats, ferrets, and most other mammals.

Q: How long does it take, and does it have to be done by a veterinarian?

A: It takes the same amount of time it takes to give any injection. It takes seconds. It takes more time to do the paperwork than implant the microchip.

No, it doesn't have to be done by a veterinarian, although it's recommended a veterinarian do it.

Q: Is it painful to my pet?

A: It hurts about as much as having blood drawn. It's a large needle. There's a pinch. A lot of people have it done when their pets are being spayed or neutered for that reason. But I've seen a lot of animals not even flinch when it happens.

Q: What does it cost?

A: If you're going to a vet just to get a microchip done, it's probably going to cost around $50. But if you have it done while your having other things done, like your regular check up, then it will probably be a bit less because you've already paid for the office visit.

People also can check with local animal shelters or rescue groups, which often do it for less.

Q: I've heard animals have died when a chip was implanted incorrectly. Is the procedure dangerous?

A: There have been some cases of complications. It's rare, but it can happen. That's why, even though there's no law that requires veterinarians implant the chips, we recommend it. Because it does matter where you put it and how you inject it.

Q: Have studies found an increased risk of cancer in pets with microchips?

A: There have been animals that have developed tumors at the site of the microchip. It's incredibly rare, compared to the millions and millions of animals that have had microchips implanted in them. It's an incredibly low risk, but it can happen.

People have to weigh that small risk against what can happen to their lost pet.

Q: How will it help me get my pet back if he is lost?

A: It's only going to help if someone picks up your pet and takes him to a shelter or veterinarian's office to be scanned for a chip. Some people think chips are like a tracker or a GPS device, but a microchip only works if someone scans the chip.

Once they get the chip's number, and the company that made the chip, they'll contact that company to find the owner. And that's one of the most important things people need to remember - the chip is only as good as the registration. A lot of people think, “OK, I've got this in. I'm done.” But if your registration isn't submitted and then kept current, it's useless. That's been a big gap. Many more pets are microchipped than are properly registered. You have to get the paperwork and make sure that chip is registered to you, with your phone numbers. And if you move or you change your phone numbers, you have to update that information.

Q: Do all shelters scan for microchips when they find a pet?

A: All shelters should scan any pet that comes in for microchips and they should do so with a universal scanner. But I can't guarantee that all shelters do that.

Q: Do all scanners used by shelters pick up all microchips?

A: Not all scanners pick up all microchips. There are more universal scanners now, but some work better than others. In an ideal world, all shelters would be using a universal scanner that works well to check every animal they find. But in reality, not all shelters have universal scanners that work well. Sometimes they'll have more than one scanner so they can find different chips. Of course, that assumes they have the time and manpower to scan every animal more than once.

And scanners also depend on using the right technique to know how and where to scan. And chips can migrate, so if they're scanning over the back and it's migrated to the side, they may not find it.

A really good thing owners can do is that at every check-up ask your vet to scan the chip to make sure it's still reading and it's still where it should be, on the back near the shoulder blades.

Q: There are several different brands available. Which is the best, and how can I be sure my shelter will be able to read that chip if she is lost?

A: Talk to your vet and your shelter to find out what is the common chip used in your area. There are different companies and they are in competition with each other. So find out what chips the scanners at your local shelter can read so you can be sure they can read the chip you're having implanted. Some chips can be more universally read than others. So talk to your vet and see what he recommends. And if people get their pets microchipped at their vet, the vet can often find the owners, even if they haven't kept up their registration with the chip company. A lot of pets are reunited with their owners, not because the owners did a good job with registration, but because the chip is traced back to the vet that placed it and then the vet finds the owners.

Q: If my pet is microchipped, does he need a tag, too?

A: Pet owners also need to understand that a microchip is only one part of your pet's identification system. Your pet also should have a collar with tags on it. With cats you want to use breakaway collars so they don't get caught when they're climbing.

You can't just assume the person who finds your pet will know anything about microchips. They might just keep your pet or give away your pet. But if your phone number is right there, everyone knows what to do with that. And honestly, that's the most important thing you need to have on there. They don't need to know your pet's name. They don't need your address. They just need to know how to contact you if they've got your pet. And make it a number with a voicemail or answering machine.

It's also important for people to realize there's no identification system that will help if your animal is lost where no one can find him. So it's important not to let your pet run loose. And no microchip can stop your animal from being hit by a car or being stolen by someone who has bad intentions.

Q: Does the U.S. use a different frequency chip than other countries? Does that mean if I take my pet to another country, their scanners won't read his chip?

A: Yes, Europe uses a 134.2 kilohertz chip. In this country we've used 125 and 128 kilohertz chips, although some companies now are implanting the European frequency chips as well. And there are scanners now that can pick up all three. But it's so important to be sure your shelters can read whatever chip you have implanted.

And if you take your pet abroad, you need to check each country's requirements. Many have regulations about not just the type of chip, but when it's implanted.