No pet left behind: How to make sure microchips get our pets back home

By Patty Khuly, DVM on May 5, 2009
No pet left behind: How to make sure microchips get our pets back home

The pet microchip industry is getting a boost from the pet owning public’s increased interest in keeping their pets close. Nonetheless, it’s the opinion of this veterinarian that the industry––and the product itself––is suffering serious growing pains as the pet owning market’s demand matures beyond what the current, lowly microchip can reasonably supply. 

For microchips to do what their manufacturers and marketers say they do, they need to conform to the basic standards for any medical device. In other words, they must be 1) safe and 2) effective. 

Here’s a brief discussion of what that means in the case of the microchip:


1. A very low rate of tissue reaction 

2. A very low severity of any adverse reactions

The microchip industry has conquered #1 (a surprisingly low percentage of pets experience any apparent effects), but it has not yet credibly addressed #2. Though only one confirmed case of microchip-associated fibrosarcoma is currently on the books, the question of cancer-causing microchips remains to be seriously addressed by the industry. 

It’s my view that grossly negative findings are insufficient for the general public without studies indicating the absence of any histopathological changes to the microchip sites for a variety of different brands in a significant group of studied animals. 


1. The microchip must not migrate (move from its desired location)

2. The microchip must survive in working order at least 15 years in any pet

3. Any microchip must be readable by all scanners

4. The microchip must be easily readable in all patients

5. Veterinarians must scan every new pet for a microchip and annually, thereafter, to ensure proper working order

6. Shelters and rescues must scan every found animal and implant a microchip pre-adoption

7. Anyone implanting a microchip must ensure registration by keeping records of the microchip number, pet and owner (as for rabies vaccines)

8. All pet owners must be informed of their responsibility to keep registration information current

9. A centralized registry for pet microchip information must be established to ensure information is not lost or deleted upon dissolution of any one registry

Lofty goals, right? More so when you consider that NONE of them is currently a reality––nor do I expect any of these problems to imminently disappear. 

Some are technical, and may well be solved by future generations of the microchip product (though I’m currently unaware of any major research and development in these areas). Others are political, and may find solutions in either industry collaboration (unlikely, given the current state of the industry’s attitude towards competition and protectionism) or government regulation (possible, especially with AVMA pressure). 

Ultimately, however, making microchips more effective will more than likely start and end with us––those of us on the ground working to make this currently inefficient technology more usable. To that end, I’ve prepared a list of what each group of users can do to make microchips work better for them and the animals they represent:

Shelter/rescue workers

1. Stay on top of recent literature that suggests the most universal kind of scanners and most technically effective microchips. (Here's a discussion of the recent studies.)

2. Use at least two different kinds of universal scanners on all pets.

3. Scan all pets in accordance with studies indicating the prescribed pattern for ideal microchip readability.

4. Scan all pets over all parts of the neck, trunk and forelimbs.

5. Scan all overweight pets twice as diligently (as overweight animal have a higher risk factor for microchip migration and poor readability). 

6. Implant most universal, most readable microchip brands in all pets pre-adoption. 

7. Ensure the microchip is still readable upon exit.

8. Keep detailed registration records for all pets (all numbers and names on file for a minimum of 15 years).

9. Counsel pet owners on the importance of keeping microchip records current. Show them how to do this. 


1. All of the above also applies, though the timing of scanning is different:

2. Hospital policy should dictate that all new pets be scanned thoroughly. 

3. Pets’ microchip numbers must be recorded in their file.

4. Annual exams should include scanning to ensure continued microchip readability and appropriate location. 

5. Ideally, veterinarians should investigate the legitimacy of new pets’ ownership status via microchip registration, though no legal liability should result should veterinarians fail to take on this onerous step. (Here's something on this emerging issue.)

Pet owners

1. Pet owners should choose their microchips wisely based on their pets’ travel activities, typical location and local shelter technology.

2. Pet owners should maintain their pets’ microchip records in a dedicated file. 

3. Pet owners should call the microchip registry annually to ensure the appropriate information is still on file. 

4. Pets should be kept lean, in accordance with the findings that demonstrate that pets’ microchips are less readable in overweight pets.

5. Pets owners should ensure their veterinarians scan their pets at least once  a year to ensure continued readability and location of the microchip. 

OK, so I think that’s enough about microchips for one week. What say you? 


Patty Khuly, DVM


Help us make PetMD better

Was this article helpful?

Get Instant Vet Help Via Chat or Video. Connect with a Vet. Chewy Health