Is Microchipping Safe? Risks and Side Effects Explained
Vet charities agree microchipping is safe, but rare reactions, failures and migrations do happen. Know what to watch for, who to tell, and how reporting to Defra works.
Microchipping is a routine procedure, and problems are very rare. Chips are made of non-reactive materials, so once in place a chip shouldn't hurt or cause your pet problems through its life. A small number of problems are recognised, though, and there's a legal duty to report them, so it's worth knowing what to watch for before you book.
What side effects can happen
Most reactions happen soon after the chip goes in and are caused by the procedure itself. The common ones are bleeding under the skin, known as a haematoma, and infection, which can show as an abscess near the site or spread and make the pet feel unwell. Occasionally a pet reacts to the chip itself with an inflammatory response.
A little bleeding at the time is normal and stops within a minute or two. That doesn’t count as an adverse event. For what the procedure itself feels like, see our page on whether microchipping hurts dogs.
Two rarer problems are worth knowing about. The British Small Animal Veterinary Association (BSAVA) notes a very small number of paralysis cases linked to the chip being implanted into the spinal cord, which it puts down to implanting technique rather than the chip itself. It also notes a very small number of cancers around the implant site, which may or may not be related to the chip.
Cats sometimes get a small swelling as a reaction to the needle. It usually settles on its own within a few days. If anything about the site worries you afterwards, contact your vet.
How often problems are reported
The most detailed UK figures date from 2014 and 2015, when the Veterinary Medicines Directorate (VMD), the government body that runs the reporting scheme, reviewed microchip adverse-event reports. The VMD concluded that the chance of an animal having a problem was very low, though it couldn’t give a precise rate because it didn’t know how many chips had been sold. No newer figures have been published, so for owners the practical reading is that the risk remains small.
If a chip stops working or has to come out
A chip only counts as failed when it can’t be detected after a full body scan with a working scanner. One missed read at the surgery isn’t a failure on its own. The most common reason an implanted chip can’t be found is that it came out shortly after implanting.
Taking a chip out isn’t a routine decision. The Royal College of Veterinary Surgeons (RCVS) says a microchip should only be removed where it’s clinically justified, with the reasons written down. If a vet does recommend removal or replacement, ask them to record it and update the database afterwards.
How to report a reaction
In England, anyone who identifies an adverse reaction or a chip failure must report it, and a chip that has migrated from where it was implanted counts as a reaction. The same duty applies in Wales.
The duty applies to everyone, not just vets, though vet practices are often the first to spot problems. Your microchip provider may offer to report on your behalf. If it’s your pet, you can tell your vet, who can report it for you, or report it yourself. The GOV.UK form lists animal owner as a reporter.
Vets and trained implanters report reactions such as injury, infection or prolonged bleeding, as well as migrations and failures. They use the microchipping adverse event reporting form and email it to [email protected]. The form asks for the chip number and maker, the implant date and site, and the event type.
After a new chip, update the record
If your pet’s chip has failed or come out and needs replacing, updating the database record is your job. The VMD does not tell microchip databases about failure reports, so nobody will do it for you. Once the new chip is in, register it with your current details. Our guide to updating your dog’s microchip details shows you how.
Chip problems are rare, but when one happens, the record on the database is what gets your pet home. Keep yours current and in your name, and the chip will do its job.
