Cat Microchip: Side Effects And Other Concerns

TL;DR: Discussing the concerns and questions about cat microchip side effects and safety. While there are a few possible side effects, they are not serious and are far outweighed by the benefits of microchips for cats. ​​

A few years ago, a stray cat showed up at our door. As he was adorable, sweet, and apparently homeless, we wanted to adopt him and brought him to our veterinarian who checked him for a microchip. Much to our surprise, she told us that he had a microchip from France, but unfortunately, the microchip was not registered. 

Luckily, we found out that a family from France lived around the corner from us. It turned out to be their cat, and thanks to the French microchip, this story had a happy ending. As you can see, microchips for cats can make a difference, but they usually won’t do much good unless they are registered. Without registered microchips, only 1.8 percent of lost cats are returned to the owners. 

Still, you might have concerns and questions about cat microchip side effects and safety. While there are a few possible side effects, for the most part, they are not serious and are outweighed by the benefits of microchips for cats. 

Are microchips safe for cats?

According to available studies, microchips are considered very safe for cats. A database maintained by the British Small Animal Veterinary Association (BSAVA) recorded only 391 cat microchip side effects out of four million cases. The most common problem is the migration of the microchip from the site of implantation. 

Microchips that migrate often find their way to your cat’s leg where a scanner might not be able to locate them. Other problems that can occur include hair loss, swelling, infection, and tumors, although these are extremely rare

A microchip that is not injected properly is more likely to cause problems. If it is too deeply embedded, it might not be able to be read by scanners, and if it is too close to the spine or inserted too forcefully, it might cause weakness or temporary paralysis. Only a professional, such as a veterinarian, should inject a microchip into your cat.

Do microchips cause cancer?

Despite rumors to the contrary, it is very unlikely that a microchip will cause your cat to get cancer. While there are reports of mice and rats developing cancer from implanted microchips, most of these cases occurred in rodents that were participating in cancer studies and in strains that were bred to be prone to tumors.

There are only two reports of cats developing tumors associated with microchips, and only one that can be linked directly to the microchip. The same is true for dogs. Dr. Barb Powers is a renowned pathologist at Colorado State University where samples from all over the west are received, and she has seen only one case of microchip-associated cancer in her entire career

In fact, any injection or other trauma has the potential to cause cancer in animals due to inflammation, and cats seem to be particularly susceptible to this type of tumor. Killed vaccines, such as rabies, feline leukemia, and FIV, are most commonly associated with cancer. However, even with these vaccines, the risk is still quite small, and it is usually outweighed by the benefits. 

What are the benefits of microchipping your cat?

The main benefit of microchipping is that it greatly increases the chances that your cat will be returned to you if he gets lost or stolen. In fact, according to AKC Reunite, “pets with microchips are up to 20 times more likely to be reunited with their owners.” Microchips also can be a lifesaver in the case of an emergency, such as a fire, hurricane, earthquake, or any other type of natural disaster.

Unlike collars with tags, microchips provide permanent electronic identification. Each one has a unique number that can be read with a microchip scanner and matched with the owner. As long as you keep your contact information up to date in a microchip registry, there is a good chance that you will be reunited with your lost cat.

Another benefit of microchips is that they enable you to travel with your pet. If you are traveling outside the United States or to Hawaii, your pet must be microchipped before you start the Health Certification process. More information can be found at the USDA Animal and Plant Health Inspection Service and the American Veterinary Medical Association websites.

Benefits overweigh any potential downsides

As you can see, there are a few potential cat microchip side effects to be aware of. There is a very small risk of an adverse reaction to an implanted microchip or that a microchip won’t be able to be read. While it is important to be aware of these possible side effects, it is generally believed that the benefits of microchips greatly outweigh the downsides.

Even if you keep your cat indoors, most cats will end up getting outside at some point. In fact, studies show that one in three pets become lost during their lifetime. If your cat is lost and ends up in a shelter without a registered microchip, there is only a small chance that he will be returned to you.

With a registered microchip, the chances of being reunited with your cat increase significantly. Animal shelters and veterinarians check for microchips before deciding to adopt out or euthanize a cat. Universal scanners that detect different microchip frequencies are making it easier for veterinarians and shelters to read implanted microchips. 

What does microchipping your cat do? What can it do, and what it can’t

Microchipping your cat involves injecting a small device, the size of a grain of rice, into your cat. This can be done at a regular veterinary visit or when your cat is having another procedure done. The microchip contains your cat’s identification number, which can be used to look up your contact information. 

Microchips are not GPS devices. They cannot track your cat if he gets lost. They do not contain medical information although some microchip registration databases allow you to enter information about your pet’s medical conditions and history. A microchip can only provide your contact information if you register it and keep it up to date. 

A microchip does not replace the need for a collar tag. Collar tags are still recommended because they can help someone locate you quickly without the hassle of taking your cat to a vet or shelter to be scanned. However, tags and collars can fall off or be removed. A registered microchip is the best way to protect your cat from being adopted by another family or euthanized at a shelter.

Can you feel a microchip in a cat?

Microchips are injected subcutaneously (just under the skin) between your cat’s shoulder blades, so you might be able to feel it depending on your cat’s size and weight. Although my cat is very small and slender, I have never felt her microchip. Microchips can migrate to other parts of the body, so there is a chance you might feel them in another place.

Can a cat microchip cause a lump?

It is not common for a microchip to cause a lump; however, you might feel a small lump under the skin where the microchip was inserted. It is also possible, but unlikely, for swelling to occur as a microchip side effect. This will usually resolve itself within a month, but if it persists for longer than that or gets larger over time, you should consult your veterinarian.

Does it hurt when getting microchipped?

Microchips are inserted under a cat’s skin using a hypodermic needle causing a pinch that feels about the same as a regular injection. The procedure requires no anesthesia or surgery. It takes only a few seconds to insert a microchip, and any pain that cats experience should be minimal and quickly forgotten.

How to tell if a cat has a microchip?

If you adopt a cat from a shelter, they should inform you that he has a microchip and provide you with the number. If you are not sure if your cat has a microchip, you can bring him to your veterinarian or to a shelter to be scanned. 

Most veterinary clinics and animal shelters have scanners; however, if your veterinarian does not have a microchip scanner, it is possible to find microchips with an X-ray. 

How much does it cost to see if a cat is microchipped?

Most shelters have scanners and will not charge for scanning. The process of scanning for a microchip is quick and easy. If you find a lost cat with no tag, it’s best to bring him to a shelter or to your veterinarian to see if he is microchipped. If the cat is found to have a registered microchip, the company can contact the cat’s owners to tell them their cat has been found.

How do you know if your cat’s microchip is registered?

If you are not sure whether your cat’s microchip is registered, it is easy to check. The quickest way to check is by using the online pet microchip lookup system. Simply enter the microchip ID number with no punctuation or spaces, and the results will be displayed.

What is the best pet microchip registration?

Since there are multiple pet microchip registration services to choose from, knowing a few things about them will help you make the best choice. You will want to choose one that has the best access to databases and technology, that protects your data, and that provides the services that will be most helpful to you. 

One good choice is AKC Reunite. As a member of the American Animal Hospital Association LookUp, it can check against hundreds of databases, and it provides a Lost Pet Alert to let local veterinarians, shelters, and volunteers know that your pet is missing. 

If your pet’s microchip is scanned, AKC is contacted. They will call, email, and text you and your alternate contacts to help reunite you with your cat as quickly as possible. They enroll all microchip brands, and they charge no annual fees or record update fees.

How to tell if a microchip registry is good?

Registries vary in what they offer and at what cost. There is also a range in quality, so choosing a good registry is important. When selecting a microchip registry, you should be sure to choose one that participates in the AAHA Universal Pet Microchip Lookup Tool. A list of participating microchipping and pet recovery services can be found at this link

You will also want a registry that offers live operators to handle communication between pet owners and shelters and one that can be reached easily by phone. Read their Privacy Policies carefully and avoid any registries that share data with vendors. Finally, speak to a representative to find out how they handle lost and found pets.