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Dog Word of the Day: Microchip

Technology today has advanced quite a lot and it's not surprising if the use of identifying integrated circuits through the use of a microchip has involved dogs. Microchips, implanted for the purpose of reducing the number of lost dogs, has become a quite popular practice nowadays, but it's important to know several facts about microchipping dogs such as the how microchip work, whether they are painful to implant, how much they cost, what to do when you must change address and any dangers associated with microchip implantation in dogs.

How Dog Microchips Work

A microchip next to a grain of rice.

A microchip next to a grain of rice.

Microchip basically consist of an identifying integrated circuit that's implanted under the dog's skin. A microchip uses what's known as passive Radio Frequency Identification technology (RFID).

What does a dog microchip look like? The chip is about the size of a grain of rice and is enclosed in bio-compatible glass. It's small enough to fit through a hollow hypodermic needle.

Typically, microchip are implanted between the dog's shoulder blades by a veterinarian using a syringe as when giving a vaccination. However, instead of injecting antigens, the hollow needle, which is larger than the average needle used for vaccines, implants the chip.

The chip contains a unique ID number encoded into its integrated circuit. It is meant to be scanned through a handheld microchip scanner which animal control officers, shelters and veterinary offices carry.

When the chip is scanned, it reveals the identification number and the phone number of the registry for the particular brand of chip, as long as the dog owner correctly registered the dog with the chip manufacturer, distributor or pet recovery service.

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Did you know? Registering the dog is the most important step in the microchip process. Failure to register a dog with a microchip means that should the dog get lost, the shelter may not be able to trace the dog back to his owners. A chip without contact information is basically useless, yet some people forget to do this! Also, important is to ask your veterinarian to scan your dog's microchip at least once per year to ensure it is still functioning and keeping your contact information up-to-date.

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Handheld Scanner Concerns 


Something to be aware of is that sometimes, for some reason or another, certain scanners may not be able to properly read certain microchip.

Microchip are inert objects that are only activated by a certain radio frequency broadcast by the scanner. The scanner must therefore send a specific radio signal of a certain frequency to read the chip

If that radio frequency doesn't match the specific frequency of radio wave necessary to activate the microchip, the scanner won't read it.

While today, more and more microchip manufacturers are trying to craft their microchip in such a way to that all scanners can read them (e.g universal scanners), some can only be read by specific scanners, which can create problems.

For example, some scanners may only detect 134.2 kHz ISO standard microchips, but might not detect the 125 kHz or 128 kHz non-ISO standardmicrochipsFortunately though, most microchips can be read after trying different scanners.

 "I can think of a couple of cases over my career where the client said they had a microchip and I couldn't find it with my universal scanner. In those cases I recommended going back to the shelter or vet who implanted the chip and have them scan it with one of their scanners." ~Dr. Chris Bern

Did you know? Microchips are not foolproof, sometimes they aren't read well because of incorrect scanning technique, presence of matted hair covering the chip, excess body fat and a collar with a lot of metal interfering, warns veterinarian Dr. Mary Fuller.

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dog pain goes away at the vet

Dog Microchip Health Concerns 

As with anything "foreign" item introduced to a dog's body, there are chances the microchip may be "rejected" or that it may cause trouble.

Both in humans and dogs, there are chances that the immune system may react to metals and other inorganic materials.

A series of studies published between 1996 and 2006, found a potential link between implanted microchips and cancer in laboratory animals. The research found that between 1 and 10 percent of microchipped mice and rat developed fast-growing sarcomas, fibrosarcomas, and other invasive cancers close-by or around the microchip.

In dogs, there have been two confirmed cases of cancer developing from microchip implants. However, the AVMA states: "Tumors associated with microchips in two dogs and two cats have been reported, but in at least one dog and one cat the tumor could not be directly linked to the microchip itself (and may have been caused by something else)."

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While these are small statistics, they are worth considering but it's important to balance out the chances of possibly losing a pet from escape versus possibly losing a pet to cancer. The WSAVA Microchip Committee came to the conclusion that the benefits of microchip outweighs the potential health risks.1

"The evidence does suggest some reason to be concerned about tumor formations."~Dr. Chand Khanna, veterinary oncologist.

Dog Microchip Pain


Does microchip implantation hurt? We found several websites say that it hurts no more than a vaccination, but we think this varies on an individual basis.

As people, dogs have different pain tolerance levels. For instance, one of our dogs yelped in pain when the microchip was implanted, while our other didn't even notice it.

According to Chewelah Veterinary Clinic, a 12 to 14 gauge needle is used for microchip implantation which is roughly the size of a belly button ring piercing.

What options do dog owners have if they are concerned about pain? They can ask for a local anesthetic or they can alternatively have the implantation done while the dog is under anesthesia such as a during a spay or neuter surgery or dental cleaning.

"At my practice we would never even consider microchipping without some local anesthetic... No matter what you have been told, the procedure hurts -- the chip is inserted with a really big 12-gauge needle!"~Dr. Karen Becker


Things to Consider

While a microchip can work wonders for re-uniting a lost dog to his family, it's still important for the dog to wear his collar and ID tags. Why is that? For the simple fact that most people do not have a handheld scanner to find your contact information. So unless, they bring the dog to a shelter or veterinarian, they may never know who the dog belongs to.

The first thing most people do when they find a lost dog is to check the collar and tags. If your dog wears a collar and tags with information on it, you're more likely to get a phone call from people who have found him rather than taking him to the shelter. It might also be a good idea to have the dog wear a tag with the chip number and registry phone number, just in case.

What happens to your dog's microchip if you must move? In that case, you will need to update your contact information by contacting the chip manufacturer, distributor or registry. Usually, this is done for a fee so that they can process the new information.

Did you know? Microchip have a tendency to occasionally "migrate" moving to other areas of the dog's body away from the original implantation site. For this reason, it's important to pass the scanner all over the dog's body so to detect it.

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The Bottom Line


Every year, thousands of dogs are lost and many are not re-united with their owners. When dogs without ID tags or microchip end up in a shelter, they risk being adopted out or even euthanized, if they cannot be traced back to their owners in a timely matter, points out veterinarian Dr. Concannon..

Also, should a dog escape and get hit by a car and a good Samaritan brings the dog to a vet, the microchip's information may allow veterinarians to get in touch with the owners quickly for approval of life-saving procedures such as emergency surgery.

Microchip are ultimately the best form of identification presently available. They stay in place for the life of the dog while collars and tags can eventually come off or be lost.They don't require a surgical procedure to implant and are also fairly cheap to implant. The average microchip implantation for dogs costs between 25 and 50 dollars with the registration generally ranging from 30 to 45 dollars. Some shelters offer free microchip implantation when a pet is adopted.

While a microchip does not have GPS capability to locate a missing pet, as of today, microchips remain the best option for re-uniting dogs with their beloved owners. It's up to dog owners therefore to make an informed decision about whether it's something they want to consider.


  • Todd Lewan, "Chip Implants Linked to Animal Tumors." Associated Press. September 8, 2007.
  • Blanchard, KT, et al. "Transponder-induced sarcoma in the heterozygous p53+/- mouse." Toxicologic Pathology. 1999;
  • Tillmann, T, et al. "Subcutaneous soft tissue tumours at the site of implanted microchips in mice." Experimental and Toxicologic Pathology. 1997;49:197200.
  • Albrecht, K. "Microchip-Induced Tumors in Laboratory Rodents and Dogs: A Review of the Literature 1990-2006."
  • Microchip Implants, Answers to Frequently Asked Questions, Katherine Albrecht, retrieved from the web on October 19th, 2016
  • Microchip-Induced Tumors in Laboratory Rodents and Dogs: A Review of the Literature 1990–2006, Katherine Albrecht retrieved from the web on October 19th, 2016
  • World Small Animal Veterinary Association, WSAVA microchip survey results – Nov. 2002

Photo Credits:

  • An RFID chip (also known as PIT tag) next to a grain of rice. No machine-readable author provided. Light Warrior assumed (based on copyright claims). - No machine-readable source provided. Own work assumed (based on copyright claims). Public Domain
  • Example of an RFID scanner used with animal microchip implants.Oscar111 -RFID scanner Public Domain
  • A vet examines a dog in New York, Archivist1174 - Own work, Photo of New York State Assemblyman Dr. Stephen M. "Steve" Katz at the Bronx Veterinary Center.CC BY-SA 3.0

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