Pet Microchip Information

Health Effects
Background (Risk Assessments)
Broken Information Chain
The Problem with Microchip Mandates
Compounded Veterinary Procedures
Cats Versus Dogs
Failures of the Microchip Tracking System
Alternative ID Methods
Recommendations for a Pet Friendly Community


Pet microchips can cause pain and illness through acute and chronic inflammation, toxins in encapsulants and electromagnetic effects.

When a microchip is implanted in a cat or dog they suffer pain through acute inflammation for at least three days.  The inflammatory response continues for approximately a month until the implant is covered with scar tissue so animals need care and considerations for some time after implant.  Implant techniques into the pets tissues and plastic coatings are intentionally designed to be inflammatory, to cause the inflammatory response that covers the microchip with scar tissue.  The American Veterinary Medical Association (AVMA) sites an independent study on beagles where only 87 of 90 implants formed the scar tissue.  So what happens with the inflammatory response when no scar tissue forms?  Does it never start or never stop?

The plastics used as sleeves or to coat or encapsulate microchips can contain toxins that migrate to the surface over time, releasing into the pet.   Parylene C is a chlorinated polymer of aromatic (benzene-like) monomers.  Plastics are also used in place of glass.  Patents describe plastic encapsulants as silicone with a polyester sheath.  There are no enforceable regulations or restrictions on what materials can be implanted in a pet as a microchip coating or encapsulant.  Cancer studies on these materials may not actually be useful because the impurities in them depend a lot on how they are manufactured.   Without regulation,  specifications and quality control, there is no way to insure safety.

These plastic coatings are said to be put on pet microchips to prevent migration, a major failure of the microchip system.  There are no third party studies that show any of them actually do that.   Are our pets being used to field test materials for medical implants?

Glass is a non-crystalline amorphous solid.  It can contain impurities also. Although the diffusion of them to the surface is very slow, there are still issues.  Lead is commonly added to glass to make it easier to process.  What are the protections from the use of lead in the glass of pet microchips?  Just what is bio-compatible glass?  One manufacturer gives heavy metal specifications for their pet microchip transponder glass as, “The heavy metal content for the elements lead, cadmium, mercury and hexavalent chromium is below 100 ppm.”   That would be 0.01%.  Does the pet guardian know to ask for specifications on the glass used for their pet’s microchip?  And just what should they be?

Pet microchips can be made with ferrous materials that give them magnetic potential.  Human microchip tests for magnetic potential are described in the FDA Guidelines.  Pet guardians are not advised of the dangers, here.  Are they warned not to use magnetic pain therapy for their pets?  The AVMA reports that surrounding tissue is not damaged during MRI, but conflicting reports exist elsewhere and MRI manufacturers give warnings.  There are questions about MRI safety due to movement, also.  Pets should have more rigorous standards for magnetic potential than humans.  But they have none.  There are no regulations on magnetic potential for pet microchips.  The magnetic potential of three different microchips are shown in the following:

Claims that pet microchips are passive, activating only when scanned may be in part true about the actual microchip but the implant also has an antenna.  The antenna is not a selective receiver and can intercept, generate current with, and re-radiate other electromagnetic waves in the environment.

There are standards for pet microchip implant sites, radio frequencies and scanners, but none that protect pets from toxins in encpsulants or set limits for magnetic potentials.

Medical microchips implanted in a sick person to manage or cure illness can benefit their health.  Implanting microchips in an otherwise healthy animal only creates illness.  Read on to find out more on just how much.


Medical microchips are an emerging industry.  The microchip was invented in 1959.  Some of the first human implants were demonstrated in 1998.  The FDA classified their use as Class II Medical Devices in October 2004 and they have been implanted in humans as such since 2006.  However, the FDA official involved in their classification was later became a highly paid employee of the first company approved for the classification.  The industry has been plagued by questions of integrity and a lack of due diligence for regulation and cancer review.  False advertising is pervasive as FDA health risk labeling recommendations for humans are not required for pets.

Animal testing has been conducted since at least the 1980’s.  Adverse event reporting has been inconsistent, with no mandatory reporting throughout the world until recently.  Some earlier data is available through the British Small Animal Veterinary Association (BSAVA).  The AVMA summarizes the BSAVA adverse reaction reports on their website.  It shows 391 adverse events reported for a period of 1996 through 2009 relating to 3.7 million registered pets with microchip implants.   Of the 391 adverse events, 301 were migration (includes lost), 36 failed and 54 were reactions.  That would indicate an event rate of 1 out of 9,462 implants, commonly sited as 1 in 10,000 and generally dismissed as insignificant.

It is a committee of the World Small Animal Veterinary Association (WSAVA)  that has established the position on pet microchip implants  that the other organizations reference as a recommendation.  It is based on the early BSAVA data. They say, “The benefits of transponder implantation, backed up with a reliable, accurate and available database, far outweigh this risk.”  Also “While it is not possible to claim that the reaction to an implanted transponder in a companion animal will NEVER induce tumour formation, the Committee is unanimously of the opinion that the benefits available to implanted animals far outweigh any possible risk to the health of the animal concerned.”  The WSAVA is a global organization that includes member nations that are major microchip producers.  They accept the Five Freedoms as standards of care but still condone the consumption of dog and cat meat while cat and dog guardians generally regard them as family members.

The UK’s Veterinary Medicines Directorate (VMD) assumed the task of adverse event reporting there in April 2014.  Mandatory microchip implant of dogs and mandatory adverse event reporting went into effect in England in February of 2015 and in Scotland and Wales in April of 2016.  The first summary report was issued for the period of April 2014 through December 2015.   The 2014 voluntary data shows 28 reports in 8 months (10.25 reports/month) for a population that would have had between 60% and 86% of dogs implanted.  This is compared to the mandatory implant and reporting  of the 2017 data with 1,044 reports (87 reports/month) with 95% of the dogs implanted.  That would indicate a factor of approximately 7 for voluntary versus mandatory reporting.

The data through the end of 2017 is shown below. The estimate for the total cat and dog population of the UK is 16 million with 8.5 million dogs subject to mandatory microchip implant.   Mandatory microchip implant for dogs throughout the UK took effect in April 2016.  The total number of implants is not tracked, but estimates at various points in time are given.  To do a good comparison to the earlier data for risk assessment, information should be collected over a similar time period, however, the data to date gives us fair estimates that indicate it is approximately ten times higher than the earlier data that has been used for many risk/benefit analysis.


Period Total AE Dog AE Migration Failure Reactions
4/2014-12/2015 1,420 1,195 729 630 61
2016 2,063 1,861 876 1,090 97
2017 1,044 843 407 584 53
Total 4,527 3,899 2,012 2,304 211

The overall data suggests an adverse event rate of approximately 1 in 3,000.  The Reactions include rejection, infection, tumors and death.

But if we look closer in the data, we find it is even higher, when adjusted for the under reporting prior to mandatory reporting. The UK Government claims that 86% of all dogs had microchips as of April 2016.  A year later, the claim is that 95% of all dogs have microchips.  Based on this, the adverse event rate is approximately 1 in 1,000, calculated as follows:

From the 2016 and 2017 adverse event data sets we extracted the following for Events First Detected the year starting April 2016:

ADVERSE EVENTS Total AE Migration Failure Reactions
All Animals               1,678            661           938             79
Dog Only               1,406            739           615             52
Dog Implants Per Event             1,048        1,994       2,396      28,333

Based on the population estimates:

Population Implanted 4/1/16 – 3/31/17
Population (9% of 8.5 million)           765,000
Births (1/12 of 8.5 million)           708,333
Total Dogs Implanted       1,473,333

The UK Government also reports that 61% (or 69%, depending on interpretation) of dogs had microchip implants as of 2012.  Another UK Government post in February 2013 claims 60% of dogs had microchip implants at that time.   This would indicate that the population base that was implanted with mandatory reporting in effect would be around one third of the 8.5 million.  So the overall rate of 1 in 3,000 at one third the population would support the 1 in 1, 000 rate.

Another way to estimate the adverse event rate would be to consider the 2017 data as reflecting the birth rate.  That would indicate the rate is 1 in 840.

The BSAVA, the UK VMD,  the AVMA and the WSAVA are not reporting on these statistics.

This mandatory reporting of Adverse Events may yet be understated as shelters do not report on pets who develop communicable diseases after being implanted with a microchip upon intake to the shelter.  Should they develop communicable diseases or even die after implant, it is treated as just another death in the shelter.

Adverse effects relating to cancer that have been validated are tumors that actually grow on the microchips.  The incidence of tumors growing on the chips is rare.  But despite the existence of these tumors, there are no known accepted, published studies on how the cancer rates of cats and dogs with microchips compare with those who do not have them.  If they exist within the pet microchip industry, the public has no access.  Although it appears that pet cancer may be on the rise, pet microchips are not being scrutinized.

Reporting tumors or other adverse events associated with pet microchips to the Veterinary FDA is not mandatory.  Four veterinarians were involved in treating this dog for cancer and never reported the tumor as an adverse microchip implant event.  Most pet guardians do not know that they can make the reports.

Manufactures distributing products in the United States include Datamars, Trovan, AVID, Altifex and Destron Fearing/Digital Angel.  These products are mainly distributed through non-profit pet identification registries with volunteers who are not trained or knowledgeable about the technology or adverse effects.  AVID won a lawsuit against Datamars in 2004 for technology infringement and making false advertising claims that harmed consumers, yet they dominate the market of today with the same practices.

With the pet microchip industry essentially unregulated, microchip mandates for animals can be used to provided a corridor for the industry to use our pets as test subjects for risky products without consent or compensation.  New products can be introduced into the microchip market without notice.  These products are frequently made available at low cost so that the product can be field tested.  Destron-Fearing set the precedent for polymer coating part of the microchip with a polypropylene cap over 20 years ago.  The polymer is supposed to be medical grade polypropylene that could be a simple hydrocarbon polymer that would have minimal impurities and additives.  But now there are microchips on the market that are coated with Parylene C, a chlorinated polymer or aromatic (benzene-like) compounds, that appears to have been introduced without cancer testing.   Datamars currently sells “the only bio-polymer microchip in the market” that is being used on our pets.  They claim it is FDA approved, but do not say what for. The FDA Center for Veterinary Medicine has no knowledge of the product.  It is sold on the internet, represented as a glass microchip.

Datamars, a Swiss livestock management company, dominates the UK market.  Their 2007 pet microchip patent includes a plastic microchip that is described as a silicon filled pet microchip with a polyester sheath, but other plastics are also referenced.  They appear to have started marketing their plastic microchip around 2012 and the North American division started promoting it for sale around 2014.  It is currently being sold on the internet without disclosing to consumers that it is not glass encapsulated.  So far as we can tell, the only thing in the packaging that distinguishes the plastic pet microchip from their glass product is the orange tip used on the syringe. That is not what is shown in the pictures on the sellers website.  There is vague reference made to the fact that it is other than a standard glass microchip, but no say of how besides it’s smaller size.  The consumer would otherwise have to discharge the microchip for inspection or otherwise research the microchip to know it is not a glass encapsulated microchip.

Third party studies, including the polypropylene cap microchip, indicate that the cap does not prevent or reduce migration.  The 2016 and 2017 UK Adverse Events that show the transponder number (985) of the Destron-Fearing polypropylene cap microchip accounts for 9% of the migration events.  While it cannot be determined from this if the cap reduces migration or not, it can be said it does not prevent it.


The FDA guidance document that is part of the human microchip classification determination lists the potential risks to health associated with microchips.  Cancer risk was not considered in the FDA review.  The recommended labeling for human microchips to mitigate the health risk are warnings about:

  • Adverse Tissue Reaction
  • Failure of implanted transponder
  • Failure of electronic scanner
  • Electromagnetic Interference
  • Electrical Hazards
  • Magnetic Resonance Imaging Incompatibility
  • Needle stick

The FDA considers pet microchips to be veterinary medical devices and they are regulated by the FDA Center for Veterinary Medicine.  The programs for adverse event reporting and advertising/labeling guidance are voluntary and regulations pertain mostly to record keeping requirements.

Manufacturers distribute their products through non-profit registries to veterinarians and pet owners directly.  They are required to label with manufacturer and/or distributors information, but generally contain no health effects warnings as this is not actually required.

So when is the pet owner informed?  How is the public informed?  Do our public information programs include these FDA warnings and health risks?  Would pet microchips become an adoptability issue if they were recognized as a health liability?


The ASPCA says statistics show euthanasia rates are dropping.  The post on their website attributes the drop to improved returns to owner and improved adoptions.   However, we smell Bullchips. The data on their page says that 0.7 million on the 1.1 million reduction is in reduced intake but they do not point that out.  Reduced intake is generally attributed to spay/neuter programs, however microchip returns to owner outside the shelter system are taking credit for that reduction without providing registry verification of the returns.  Otherwise, improved adoption and return to owner together would account for no more than 0.4 million of the reduction.  The returns to owner improvement claims do not stand up to scrutiny because if there are more returns to owners, there would be fewer adoptions.   Why is this large organization perpetuating the misconception that microchips (returns to owner) reduce euthanasia instead of pointing out the obvious that  spay/neuter is causing the largest decrease?  This is how the public is mislead about the benefit of microchips as they detract from spay/neuter program credits and resources.

Microchip technology has not been readily adopted by pet owners and the microchip special interests have been promoting mandates through pet shelter programs.  Best Practice recommendations include methods for forcing mandates on the public through local ordinances and enforcing them through the shelter programs by refusing to release or return a pet unless it is implanted with a microchip.  Pet microchip mandates are generally imposed as a remedy for stray pets and many are mislead to believe it reduces euthanasia.  Most stray animals, particularly cats, do not have owners and are more often the product of overpopulation than pets getting lost.  The remedy to overpopulation is spay/neuter.  When pet overpopulation is controlled, there is minimal need for euthanasia and so it becomes less of a threat to a lost pet.

Microchip mandates do not solve pet overpopulation problems and detract from resources that could be used towards spay/neuter.  The adverse health effects of pet microchips on feral cats who are implanted actually creates a need to TNVR (Trap, Neuter, Vaccinate, Return) more cats for it to be effective for population control. There are multiple means of pet identification that do not cause pain, illness and exploitation.

Microchips mandates cause more problems than they solve.  In summary:

  • The pet microchip industry is essentially unregulated, making it full of risk and liability.  The safety of pet microchips is persistently misrepresented by the manufacturers and distributors.  Enforceable standards for safety do not exist.  Pet guardians are not accurately informed of the risks.
  • Compliance with the mandatory microchip laws is costly.  Manufactures market risky microchips for field testing and low quality microchips at low cost to shelters and humane organizations trying to manage costs on a low budget, under mandates.
  • Pet overpopulation is best managed with spay/neuter programs and TNVR for cat feral populations.
  • Implanting a microchip in a pet:
    • is an unessential veterinary procedure that compounds risks and interferes with procedures for essential public health vaccinations and spay/neuter procedures that are essential to population control.
    • influences the individual circumstances of the pet, but does not substantially affect the bottom-line euthanasia rates of adoptable pets in the community where overpopulation is an issue.
  • Pet microchip mandates:
    • provide manufacturers with opportunity and protections to use our pets for nonconsensual experimentation as they can distribute unconventional, risky and harmful microchips,  without notice or labeling.
    • create a hostile environment for pets and pet owners who know the risks and would chose not to implant a microchip in their pet.
    • should include mandatory adverse event reporting and a liberal medical exception or otherwise be revoked.
  • Alternatives to microchips for pet identification exist that do not involve pet health risks, pain and exploitation. The key to good pet identification and retrieval systems is the registry.


There is a common belief that pet microchips are safe to implant in kittens as young as two months that weighs at least two pounds.  There is also a common belief that it is safe to sterilize a kitten at that age.  It has furthermore become practice to do these two procedures at the same time, particularly when there is a mandate for microchip implant.  Shelter animals seem to be the target of these procedures and many of the kittens and puppies are also at higher risk as orphans.  And they also need their vaccinations.  Little consideration appears to be given to the level of risks accumulating with all these veterinary procedures or elements of experimentation and cruelty.

The rapidly developing medical fields of inflammatory and auto-immune diseases  identifies the health risks of these procedures and how they promote disease.  Inflammatory illness is a valid basis for medical exemption from vaccination, including rabies.  The impact of too many procedures too soon may well be that our pets are not just less healthy, they may become less safe.

Trap, Neuter, Vaccinate and Return (TNVR) has become a proven means of reducing cat overpopulation.  As the cat is not just a predator, but is also prey in the wildlife system, consideration must be given in both respects.  Concerns over TNVR cats as predators have generally been disproved.  However, cruelty concerns about them as prey also exist.  Feral cats do poorly in captivity and must be returned as soon as possible after veterinary procedures are performed, even though they may still be vulnerable.  To add the unnecessary veterinary procedure of implanting a microchip to the more essential procedure of vaccination, spay/neuter and eat tipping leaves them more vulnerable as prey and raises cruelty issues.

The management of feral cat overpopulation is a daunting problem, just based on the shear numbers.  TNVR is most effectively targeted in areas where there is human/feline interaction.  However, the remaining population provides a reservoir of untreated cats that will fill any vacuum left by a treated feral that dies.  The additional health burdens of the microchip that reduce the survival of the feral, creates a need for more animals to be treated in order to manage the population.  Compounding the TNVR treatments with microchip implant is counterproductive.


The microchip risk/benefit is different for cats and dogs.  Stray cats can be pests but are not the same level of threat to public safety that dogs can be.  Cats are less conducive to ownership than dogs are and should be managed differently.

Cats do not get the same return to owner benefits from microchip implants that dogs do as they are 7-10 times more likely to find their own way home after being “lost” than dogs are.  That is another reason why TNVR is a good alternative to euthanasia for stray cats.  Microchip implant is not necessary and even counterproductive to their survival.  After TNVR with an ear tip, they are best left alone unless obviously sick or in need of help.

In the shelter, cats show fewer returns to owner than dogs do but the improvement claimed for microchip implanted animals is still quite similar, with 37% of cats returned and 30% of dogs returned that would not otherwise have been.  Is this an indicator of the system efficacy or the care and concern of the guardian of the pet?  Considering the UK microchip migration and failure rates of approximately 0.1%, that would point to the registries as the problem.  Of course, they blame the pet guardians for inaccurate information in the registries.  Are we to believe that 2 out of 3 people who lose their pet do not care to update their registry?


There is very little information on just how many pets get returned to owner because of microchips.   The available data is a little old and suggests only about 1/3 of lost pets with microchips are returned to their guardians who would otherwise not have been returned.

Failure of microchip tracking systems include:

  • Migration
  • Scanner Failure
  • Registry Problems
  • Chip Failure
  • Adverse Reaction

All pet identification system are limited in efficacy by their registries.  The key to recovery is to have an accurate registry database.  As a first step to registration, the pet owner must know the pet microchip transponder number and how it is registered.  A multitude of microchip registries have emerged with databases that are poorly staffed and maintained.  Some are not even available by phone contact so if you have a problem you can fill out the web form and maybe they will (or not) get back to you before your pet has been euthanized.  And you better check the privacy policy.  Attempts to unify the search has been only partially successful and is no better than the information contained in the many poorly maintained databases.


Conventional ID methods for cats and dogs include a collar and tag.  Some animals will have a tattoo.

Ear tipping of feral cats has also been done for some time as a means of identifying them.

Older microchips that do not conform to ISO standards may be missed with an ISO compliant scanner.  However, universal scanners have become available that can read them.

God gave our pets a unique identifier.  Yes, their loving noses.  Each dog and cat has a nose print as unique as our fingerprints.  Patents exist for nose print identification systems.  However, no active services appear to be currently available.  The Canadian Kennel Club has been accepting dog nose prints as proof of identity since 1938.

There are active registries for the facial recognition of cats and dogs.  The Petco Foundation sponsors Finding Rover .  There is also an app at Pip My Pet

With the facial recognition and finger (nose) print technologies of today, it is absolutely not necessary to use harmful invasive technologies to have permanent identifications of pets.  Their loving faces and noses are certainly more reliable than a microchip.  Microchip implant and registration is a failed tracking technology that has become abusive.  There is no excuse for mandating all our pets be subjected to the pain and health effects of the microchip.


Managing a stray and feral population, particularly of cats, can be a daunting problem.  They reproduce at rates that are way over sustainable levels.  Females reproduce themselves to death and most of their kittens do not survive.  Humans who try to rescue them flood the system with more animals than there are homes for.   Then comes the euthanasia of adoptable pets.

TNVR is currently the best remedy.  However, the shear number of cats that need to be treated are also a daunting problem.  Animal control agencies and rescue groups can be overloaded.  This is a community problem and a community that does not want pets euthanized must participate to solve the problem.

While government agencies favor mandates, fewer than 20% of pet owners want their pets implanted with a microchip.  Most people who aid ferals and strays would have similar views.  Those views are supported by the information we are posting on this site.   TNVR is most effectively targeted in areas where stray and feral cats interact with humans.  To achieve that, people must be comfortable with identifying cats for treatment. The needed community participation will not happen if there is a microchip implant mandate for these cats.  The recommendations to promote community participation to remedy lost pet and overpopulation problems are:

  • Pet Microchips
    • Mandatory microchip implant ordinances for the general population should be revoked to prevent problems from compounded veterinary procedures, conflicts with rabies vaccination, liabilities from experimental and risky products and obstacles to public engagement.  They should otherwise include mandatory FDA adverse event reporting and liberal health exceptions.
    • Microchip implants should not be promoted without informing the responsible party of the risks.   FDA Microchip Guidelines and compliance with  Veterinary Devices should be reviewed.
    • Any working microchip should be acceptable ID and a pet with such should not be implanted with another.
  • Registration and Public Engagement
    • Priority should be given to participation in pet registration and alternative ID should be accepted from pet owners who are aware of the health risks from microchip implants and find them unacceptable for their pet.
    • Facial Recognition (FR) should be incorporated into protocols for identifying lost pets. A digital FR photo could serve as ID in the registration database.
    • The facial recognition website FindingRover is free, offers partnerships and has adoption options.
    • Priority should be given to promotion for adopting and returning pets. A good facial picture for FR and a good full picture would promote returning lost pets and marketing pets for adoption.
    • Nose Print identification should be given consideration if the technology becomes available.
  • Public Safety and Population Control
    • Rabies vaccination should be given primary priority for public safety and sterilization given priority for population control.  Laws involving pediatric veterinary procedures should be limited and should not include pet microchip implantation mandates.
    • Rabies vaccination and spay/neuter compliance guidelines should match the current state of veterinary practice and owner beliefs and the registration database should automate progressive warnings of non-compliance with enforcement limits reasonable and clearly set.
    • TNVR and other spay/neuter programs should be the primary means of cat over-population control and priority should be placed on their vaccination, spay/neuter and ear tipping with microchip implantation discretionary as the last priority.  Cats need care and consideration following microchip implant for over three days and for weeks afterwards.   No one should be implanting them if they cannot provide the needed care.