"A tiny chip can make the difference between a lost pet staying lost or finding their way home — but not all microchipping is done correctly, and the details matter more than most people realize."— Julie Schwenzer
Episode summary
Most pet owners think microchipping is a one-and-done safety net. Dr. LoSasso explains why that assumption is often wrong — and why the chip itself is rarely the problem. In this episode, he walks through what a microchip actually stores, why so many scanned chips still can't be traced to an owner, and what pet parents should be doing to make sure theirs actually works when it matters.
The chip itself holds almost nothing: no battery, no owner name, no phone number — just a manufacturer identifier and a unique number. When his team scans a chip on an incoming patient, that number has to be phoned in to the chip company, which then looks up whoever registered it. That system only works if someone actually completed the registration. Shelters and breeders frequently implant chips and hand owners paperwork to finish the process themselves — and a lot of owners never do. The result, Dr. LoSasso says, is that only about 30% of microchipped pets returned to shelters have current data actually tied to their chip.
He also covers a less obvious failure mode: pets can end up with multiple chips if a lost or surrendered animal gets re-chipped without anyone checking for an existing one first. Most emergency hospitals and shelters now carry universal scanners that catch multiple manufacturers and protocols in one pass, but he still recommends a full, deliberate scan rather than stopping at the first hit.
"It doesn't the chip doesn't somehow flash with the owner's information because there's no way to implant that on the chip. All it comes up with is a company name and a number — and that's who you have to contact."— Dr. Michael LoSasso, DVM
Cats are the other blind spot. Owners of indoor cats often assume a chip is unnecessary since their cat "never leaves the house" — but doors get left open, storms spook animals, and Halloween's constant door traffic makes it one of the riskiest nights of the year for escapes. Dr. LoSasso describes treating a hit-by-car cat whose registered chip let his team reach the owner immediately and involve them in treatment decisions — something that almost never happens with an unchipped cat.
Keep your microchip registration current
Registration lapses are the real failure point, not the chip itself. Dr. LoSasso suggests picking one day a year to verify your information with the chip company — he uses July 4th, the same day fire departments recommend checking smoke detector batteries, since fireworks also send a lot of pets running that night. Update it any time you move or change your phone number.
Questions answered in this episode
The following questions are answered by Dr. LoSasso in this episode, drawn directly from the conversation. These are real clinical answers from a practicing emergency veterinarian with 30+ years of experience.
No. Dr. LoSasso explains that a microchip has no battery and stores nothing but a manufacturer identifier and a unique number — it does not transmit your name, phone number, or address. When a chip is scanned, the clinic gets that number and has to call the chip company, which then looks up the owner on file and contacts them. If the registration was never completed, or the information is outdated, that lookup goes nowhere.
Dr. LoSasso says the chip itself almost always works — the failure is registration. Shelters and breeders often implant a chip and hand owners paperwork to complete the registration themselves, and many never do it. He cites a striking number: only about 30% of microchipped pets returned to animal shelters have current owner data actually linked to their chip. An unregistered or outdated chip can be scanned successfully and still lead nowhere.
Dr. LoSasso recommends checking your registration any time you move or change your phone number, and suggests picking an annual reminder date — he uses July 4th, the same day fire departments recommend checking smoke detector batteries, since a lot of pets also go missing around fireworks that night.
Yes. Dr. LoSasso explains this happens when a pet is re-chipped without anyone checking for an existing chip first — often after being lost, surrendered, or passed through a shelter or rescue. Most emergency hospitals and shelters now use universal scanners that can detect multiple chips and multiple manufacturer protocols in one pass, but he still recommends a thorough, deliberate scan rather than stopping at the first chip found.
Dr. LoSasso strongly recommends it. Owners often assume an indoor-only cat doesn't need a chip, but doors get left open, storms spook animals, and Halloween — with its constant door traffic — is one of the highest-risk nights of the year for pets escaping. He describes treating a hit-by-car cat whose registered chip let his team reach the owner immediately and involve them in treatment decisions, something that almost never happens with unchipped cats.
Microchips are typically implanted between the shoulder blades, at the back of the neck. Dr. LoSasso notes they can migrate over time — sometimes ending up down near the chest wall — which is why his team does a full-body scan rather than checking only the standard location.
JulieA tiny chip can make the difference between a lost pet staying lost or finding their way home, but not all microchipping is done correctly, and the details matter more than most people realize. So, pet owners are generally aware of microchipping, but maybe they don't understand the right way to have their microchip in place. Can you explain what you deal with at your clinic?
Dr. LoSassoSure. We don't actually implant a lot of microchips in our emergency hospital — it's really not an emergency thing — but we certainly read them quite frequently, and it does make a difference. The challenging part isn't so much the technique or the company. There are several companies that make microchips, and there are still several different protocols with which they're made, so a specific reader is necessary. A lot of us have universal readers now that can read multiple different kinds, and theoretically can read all of them. The real hurdle is getting pet owners to understand that once that microchip is implanted, you have to do the paperwork. Shelters will implant chips and give you a dog that's already got one, along with paperwork that says "send this to this company, because that's who we microchipped it with, and get your data associated with that chip."
Dr. LoSassoYour dog is brought in by a good Samaritan — whether he's out wandering because your back gate blew open during a thunderstorm, or the July fireworks freaked him out and he went over the fence, and he needs emergency help. We scan, we find a chip, and it says it's registered to the county animal shelter. That doesn't help us find owners. It doesn't help us get to you so we can make emergency decisions. It is frustrating: of the pets returned to animal shelters, only about 30% of the microchipped ones actually have current data tied to that chip. So it's a good habit to get into. Fire departments will tell you to check the batteries in your home smoke detectors every July 4th — well, maybe that same day you log on to your microchip company's website and just verify you didn't forget to update a phone number, or that you moved and totally forgot to update that information. It's a little different today, now that we all carry our phone numbers with us no matter where we go and hold onto them longer than we hold onto homes.
Dr. LoSassoThe interesting thing is when we run into dogs with multiple chips. Sometimes an owner has chipped a dog, but the dog gets lost or is surrendered, and whoever implants a second chip doesn't check for an existing one first — you don't have to have a reader to implant a microchip. So some dogs come up with multiple chips. Ideally, in that case, you'd like both of those chips pointing to you if it's your dog. If you ever have any question, ask your veterinarian to scan the chip and see who it comes up with, what information is there — they can tell you the numbers of the chips in case there are multiples. You may still have to call the company to find out, because as the owner, you don't get immediate access to that information just by scanning. You get a microchip number, then you call the company, and the company calls whoever's on file. That creates a privacy barrier for the person the chip is registered to. When we find a chip, we've got to call the chip company to get the owner's information — the chip itself doesn't somehow flash with that information, because there's no way to store it on the chip. All it has is its own number — no battery, nothing — just a transponder that responds to the reader. All it comes up with is a company name and a number, and that's who you have to contact.
Dr. LoSassoWe ran into a big problem last year, or maybe the year before — one of the chip companies actually went out of business. If that happens, the microchip in your pet isn't helpful or valid anymore, and hopefully they informed those owners so they could get a second chip implanted. Otherwise, you don't have that method of identification. Microchips are also useful for proving ownership — we see cases where somebody will say "no, this is my dog," and you can prove it: "actually, I had it chipped four years ago, this is definitely mine." I don't think we run into a lot of those situations with pets, but I'm sure it's come up at least once. With livestock or poultry, I've had to do that with chickens crossing international borders — they have to be microchipped, and that chip has to be associated not only with the bird but with certain test results. It can become a big deal when you're moving animals across international boundaries — probably not a big thing for the pet owners listening, but it is useful.
JulieIs there a risk that in some clinics they read one chip and then just go down that route without investigating if there's another one?
Dr. LoSassoI think there's absolutely the potential for that — it was a bigger potential back in the day, when microchipping was first starting to take off in the late '90s, and you'd have one company's reader and another company's reader, and sometimes those readers would say "unrecognized chip" just to signal there's a chip there, it's just not theirs. Some wouldn't read other chips at all. So if you had multiples, that was a real risk. Now, most emergency hospitals, animal shelters, everyone routinely scanning chips is using a so-called universal scanner that will read all the different radio protocols and at least identify a company and a number, regardless of whose it is.
JulieWhat about cats? You've mentioned that a lot of cats aren't microchipped — what problems do you run into with that?
Dr. LoSassoThe problem is people say "my dog, I take him out for a walk and he's gotten out, or the gate blows open in the backyard" — but "my cat never leaves my house." Well, maybe your cat never leaves the house, and maybe he does. Maybe the front door blows open, maybe there's a severe storm and they get spooked too. Halloween is the number two day for dog loss, and the reason is the front door is open and shut, open and shut, and they squirt out sometimes. Cats do the same thing, and people assume cats don't wander, so they don't need the chip. Recently I took care of a hit-by-car cat brought in by a good Samaritan, and it shocked me when we found a chip — and even more surprising, it was associated with an owner, and we could make medical decisions with somebody who knew where their pet was, knew what condition it was in, and could be involved in the care. Otherwise they would have never known what happened to their cat, and we would never have known who that cat belonged to. I'd encourage everybody, dog or cat, to really consider microchipping and updating the company with your information.
JulieThose are some great tips. Where is the microchip usually placed?
Dr. LoSassoUsually we place it in what I'd call the withers — I'm an old horse guy — right between the shoulder blades, back of the neck. It's thick skin, doesn't hurt much when you implant it. That's where almost all of us put them, so that's where almost all of us look for them. Doesn't mean they can't wander through the body over time — sometimes they'll end up down on the chest wall. They migrate sometimes, so we do a pretty good once-over scan just in case.
JulieThank you so much for breaking that down. I wish vaccination records were associated with microchip records too — that would be helpful.
Dr. LoSassoIt would be amazing if there was some kind of two-way communication like that. I'm sure we're not that far away from having the technology, but you're talking about a database link, and we've got a long way to go for medical records to connect that way. But I'd agree — that'd be lovely.
JulieEspecially when somebody gets bitten by a dog — like, do I need a rabies shot now?
Dr. LoSassoRight, right.