Most vets have scanners available to read the most common systems out there: Home Again, and AVID. Once you have the ID number from the chip (which will also tell you the company) you can contact them. When I adopted Sugar, she was already microchipped from her prior owner, with AVID. I got the number and for a small fee ($9 2 years ago) I was able to update her file to my info.

The scanner for AVID will read AVID chips, and will indicate that there is a chip present, which can not be read, for all other companies. The same for the scanner from Home Again. There are universal scanners, which will read either company, and some vets have that type.

When I adopted Lacey, I had her microchipped from AVID as well. Each company offers discounts for multiple pets, so it made sense for me to stay with AVID.

Then came Marlin's turn. My vet no longer offered AVID. Marlin has a chip from Home Again, but I have not sent in the registration yet. I still hope to get him chipped with AVID and just add him to my existing account.

Why? AVID is a one time fee. Home Again is an annual subscription. Yes,each offers a different type of service.

With AVID, you report a pet missing. Then, if a vet /shelter/pound CHECKS WITH THEM on a pet brought in, they will advise that the pet has been reported missing, and you get contacted.

With Home Again, if you report your pet missing, Home Again sends out faxes to area vets with all the info, and the pet's photo if you have one on file. They also send this info out to shelters and dog pounds in your area, IF the shelter / pound is on file with them. I don't know what is involved for the shelter or city pound to be "on file."

I really don't need to be paying an annual fee. I can easily run around to my local vets and shelters in an emergency, I've done it when one of my cats has gone missing.

Those 2 companies are national. There are also local microchip companies, which service a set geographic region. Only vets in that area are going to have scanners which can read the chip.

So this is what I would suggest:
- take the pet to the vet and have the chip scanned, get the company name and the ID number.
- decide if you want to continue with THAT company, or switch to another company.
- staying with that company, then go to their web site, contact them to update the info
- changing companies, find a vet who will use the microchip of the company you want, and have a new microchip injected. Then register it.