Microchip Implant (animal) - Cross-compatibility and Standards Issues

Cross-compatibility and Standards Issues

In most countries, pet ID chips adhere to an international standard to promote compatibility between chips and scanners. In the US, however, three proprietary types of chips compete along with the international standard. Scanners distributed to US shelters and vets well into 2006 could each read at most three of the four types. Scanners with quad-read capability are now available and are increasingly considered required equipment. Older scanner models will be in use for some time so US pet owners must still choose between a chip with good coverage by existing scanners and one compatible with the international standard. The four types include:

• The ISO Conformant Full Duplex type has the greatest international acceptance. It is common in many countries including Europe (since the late 1990s) and Canada. It is one of two chip protocol types (along with the "Half Duplex" type sometimes used in farm and ranch animals) that conform to International Organization for Standardization standards ISO 11784 and ISO 11785. To support international/multivendor application, the 3-digit country code can contain an assigned ISO country code or a manufacturer code from 900 to 998 plus its identifying serial number. In the US, distribution of this type has been controversial. When 24PetWatch.com began distributing them in 2003 (and more famously Banfield Pet Hospitals in 2004) many shelter scanners couldn't read them. (Some still can't; asking local shelters about this is still a good idea.) At least one Banfield-chipped pet was inadvertently euthanized.

• The Trovan Unique type is another pet chip protocol type in use in US pets since 1990. Patent problems forced the withdrawal of Trovan's implanter device from US distribution and they became uncommon in US pets, although Trovan's original registry database "infopet.biz" remained in operation. In early 2007, the American Kennel Club's chip registration service, AKC Companion Animal Recovery Corp., "akccar.org", which had been the authorized registry for HomeAgain brand chips made by Destron/Digital Angel, began distributing Trovan chips with a different implanter. These chips are read by the Trovan, HomeAgain (Destron Fearing), and Bayer (Black Label) readers. Despite multiple offers from Trovan to AVID to license the technology to read the Trovan chips, AVID continues to distribute readers that do not read Trovan or the ISO compliant chips.

• A third type sometimes known as FECAVA or Destron is available under various brand names. These include, in the US, "Avid Eurochip", the common current 24PetWatch chips, and the original (and still popular) style of HomeAgain chips. (US HomeAgain and 24Petwatch now can supply the true ISO chip instead on request.) Chips of this type have 10 digit chip numbers. This "FECAVA" type is readable on a wide variety of scanners in the US and has been less controversial, although its level of adherence to the ISO standards is sometimes exaggerated in some descriptions. The ISO standard has an annex (appendix) recommending that three older chip types be supported by scanners, including a 35-bit "FECAVA"/"Destron" type. The common Eurochip/HomeAgain chips don't agree perfectly with the annex description, although the differences are sometimes considered minor. But the ISO standard also makes it clear that only its 64-bit "full-duplex" and "half-duplex" types are "conformant"; even chips (e.g., the Trovan Unique) that match one of the Annex descriptions are not. More visibly, FECAVA cannot support the ISO standard's required country/manufacturer codes. They may be accepted by authorities in many countries where ISO-standard chips are the norm, but not by those requiring literal ISO conformance.

• Finally, there's the AVID brand Friendchip type, which is peculiar due to its encryption characteristics. Cryptographic features are not necessarily unwelcome; few pet rescuers or humane societies would object to a design that outputs an ID number "in the clear" for anyone to read, along with authentication features for detection of counterfeit chips. But the authentication in "Friendchips" has been found lacking and rather easy to spoof to the AVID scanner. Although no authentication encryption is involved, obfuscation requires secret information to convert transmitted chip data to its original label ID code. Well into 2006, scanners containing the secrets were provided to the US market only by AVID and Destron/Digital Angel; Destron/Digital Angel put the decryption feature in some, but not all, of its scanners possibly as early as 1996. (For years, its scanners distributed to shelters through HomeAgain usually had full decryption, while many sold to vets would only state that an AVID chip had been found.) Well into 2006, both were resisting calls from consumers and welfare group officials to bring scanners to the US shelter community combining AVID decryption capability with the ability to read ISO-compliant chips. Some complained that AVID itself had long marketed combination pet scanners compatible with all common pet chips except possibly Trovan outside the US. By keeping them out of the US, it could be considered partly culpable in the missed-ISO chips problem others blamed on Banfield. In 2006, the European manufacturer Datamars, a supplier of ISO chips used by Banfield and others, gained access to the decryption secrets and began supplying scanners with them to US customers. This "Black Label" scanner was the first four-standard full-multi pet scanner in the US market. Later in 2006, Digital Angel announced that it would supply a full-multi scanner in the US. In 2008 AVID itself announced a "breakthrough" scanner, although as of October 2010 AVID's is still so uncommon that it's unclear whether it supports the Trovan chip. Trovan itself also got the decryption technology in or before 2006, and now provides it in scanners distributed in the US by AKC-CAR. (Some are quad-read, but others lack full ISO support.)

Numerous references in print state that the incompatibilities between different chip types are a matter of "frequency". One may find claims that early ISO adopters in the US endangered their customers' pets by giving them ISO chips that work at a "different frequency" from the local shelter's scanner, or that the US government considered forcing an incompatible frequency change. These claims were little challenged by manufacturers and distributors of ISO chips, although later evidence suggests the claims were disinformation. In fact, all chips operate at the scanner's frequency. Although ISO chips are optimized for 134.2 kHz, in practice they are readable at 125 kHz and the "125 kHz" chips are readable at 134.2 kHz. Confirmation comes from government filings which indicate that supposed "multi-frequency" scanners now commonly available are really single-frequency scanners operating at 125, 134.2 or 128 kHz.) In particular, the US HomeAgain scanner didn't change excitation frequency when ISO-read capability was added; it's still a single frequency, 125 kHz scanner.

For a time, Banfield Pet Hospitals advocated and practiced double chipping with both ISO and "FECAVA" chips. (By December 2009 they had switched to ISO-only.) But shelter scanners typically stop after finding one chip so any additional chips might go undetected. And since it's impossible to predict which chip will be found first, reliable identification thus requires that all of an animal's chips be kept on file and updated for life. )Presumably Banfield's enrollment forms had a space for "second chip number" and the on-line enrollment forms of most registries could use some improvement in this regard.) For best protection, the owner of a multi-chipped pet may want to enroll each chip separately in its most customary or manufacturer-provided registry.

(For users requiring Shelter-Grade certainty, this table is not a substitute for testing the scanner with a set of specimen chips. One study cites problems with certain Trovan chips on the Datamars Black Label scanner. In general the study found none of the tested scanners to read all four standards without some deficiency. The study predates the most recent scanner models, however.)