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Microchip Identification Guidelines

On this page you will find the Microchip Identification Guidelines including the following points;
  • Microchip implantation sites for small (companion) animals
  • Enhancing Reader Performance
  • Microchip FAQs
Read the Microchip Identification Guidelines in your language: Issues pertaining to microchip technology (ie communication protocol) have been the thrust of standardization efforts in recent years; initially by microchip user groups and then through the International Standards Organization (ISO).

Fortunately, these efforts have resulted in the adoption of global standards (ie, ISO 11784 and 11785) that have facilitated wide spread implementation of microchip identification thanks to stronger marketplace confidence. However, despite these standardization efforts, the identification network is ineffective if the reader and microchip cannot come in close enough proximity to communicate with one another, thereby providing the animal's unique identification number. To optimise this interaction, the international veterinary community has been diligently working on standardized microchip implantation sites for various species of animals.

This document details both recommended implantation sites as well as providing information on geographic and species variations (where they exist). Beginning with dogs and cats, it also provides information on agricultural animals, other mammals, amphibians, avians and reptiles. There is also a section providing recommendations on ensuring the proper function of the microchip reader, which is an integral, and often overlooked, component of the overall microchip identification system.

Please disseminate this information to your membership, thereby increasing user awareness and adoption of these standards. Cooperatively, we can ensure the viability of this technology well into the future.

Standardization of microchip implantation sites is essential to the overall integrity of a radio frequency identification (RFID) system. This is especially relevant to FDX based communication protocols since their effective interrogation distance, the distance between reader and transponder, is relatively short. However, although standardized implantation sites are critical, one cannot overlook the importance of a functional reader in the identification of an implanted transponder - without this, the system fails. The following points are the recommendations of the World Small Animal Veterinary Association (WSAVA) Microchip Subcommittee for implantation sites in small (companion) animals. Attached to this document are suggestions regarding enhancing reader performance as well as currently recommended implantation sites in species other than small (companion) animals. It is up to the individual veterinarian to assess the need for the use of a local anaesthetic. Aseptic technique, as with any injection, is recommended.

Microchip implantation sites for small (companion) animals

Canine and Feline

In the canine and feline, there are two currently recognized implantation sites in use:
  • The transponder (microchip) is implanted subcutaneous on the dorsal midline just cranial to the shoulder blades or scapula. This is the standard implantation site in all countries (including the United Kingdom [Wales, Scotland, England, and Northern Ireland] and the Republic of Ireland) excluding those of Europe.
  • The transponder (microchip) is implanted subcutaneously in the midway region of the left neck. This is the standard implantation site in continental Europe (excluding the United Kingdom and the Republic of Ireland - see above).
  • Until one common global site can be agreed upon, it is imperative that scanning concentrate on the implantation site commonly used in that geographic locale. Should an animal scan negative, it is strongly recommended that the alternative site in use, as defined above, also be scanned.

Recommended implantation sites in other species of animals

In bilaterally symmetrical species, microchips should be implanted on the left side (unless used as an aid in the identification of sex - in this case males are implanted on the left, females on the right where applicable).



In the equine, there are two recognized implantation sites currently in use
  • The microchip is implanted within the nuchal ligament in its middle third or at the halfway point between the ears and the withers. This is the recommended implantation site in all countries except Australia.
  • The microchip is implanted in the musculature of the left neck or the anterior injection triangle. Clipping of the hair, local anaesthetic and aseptic technique is required. This is the recommended implantation site in Australia. Due to the use of two implantation sites, please review and follow the scanning procedures as discussed previously under canine and feline.

Agricultural Animals

The implantation site for the bovine, ovine, porcine and caprine or other species used for meat production is subcutaneously at the base of the left ear on the scutiform cartilage. It is strongly recommended that any implanted food producing animal should carry an external identifier to indicate that a microchip is present so that it can be recognised and recovered at slaughter. Local trade or government guidelines must govern the use of implanted microchips in food producing species as in some situations their use may not be permitted.


Subcutaneously on the left side of the tail in the main caudal fold.

Hyrax and Loris

Subcutaneously on the left side of the intralumbar area.

Alpacas (as per Australia)

Subcutaneously midway on the left neck of top of the head behind the left ear.

Other mammals

If the adult length is >17 cm from the backbone (spine) to the shoulder blade - subcutaneously at the base of the left ear. If <17 cm - subcutaneously between the shoulder blades.


The microchip is to be implanted into the lymphatic cavity. The implantation site should be sealed with tissue glue.


>5.5 kg adult weight and/or long-legged: subcutaneously at the base of the neck. <5.5 kg. adult weight: intramuscularly in the left pectoral muscle. Direct the implanter in a caudal (downward) direction. Use tissue glue and digital pressure or a suture to seal the implantation site.



Up to four days old - implanted in the piping muscle behind the head on the left.

Older birds

Subcutaneously in the left thigh.


Implanted in the dorsal midline in the s/c lump (Australia).

Penguins and vultures

Subcutaneously at the base of the neck.


>30 cm in length: on the left side at the anterior base of the dorsal fin. <30 cm in length: on the left side into the coelomic cavity.



Left hind limb socket. Use a subcutaneous site in small chelonians, an intramuscular technique in large species as well as small species with thin skin. The implantation site should be sealed with tissue glue. Hibernating species should be implanted several weeks before the end of their active season in order to allow healing before hibernation.


Subcutaneously anterior to the nuchal cluster.


>12.5 cm snout to vent length - subcutaneously in the left inguinal region. <12.5 cm snout to vent length - intracoelomic.


Subcutaneously on the left side of the neck, twice the length of the head from the tip of the nose.

Note: special recommendations have been made for implantation sites to be used in particular applications. It is recommended that primates kept in cages should be implanted intramuscularly in the back of the right forearm so that the microchips can be conveniently read while the animal grips the bars of its cage. Similarly, the recommendation is that big cats should be implanted in the shoulder region so that they can be read as they walk backwards and forwards while brushing against the bars of their cage. Such sites are different from implantation sites used by other operators. These sites should only be used in animals which, after implantation, will stay in one facility where the sight of the microchip is known to all operators and there is no risk of the microchip being missed by an operator failing to scan the unusual location.

Enhancing Reader Performance

An often-overlooked factor in reader (scanner) performance is the user. How the user cares for and applies the reader can dramatically impact on reader performance. Fortunately, it is an area over which we, as users, have complete control, regardless of the manufacturer, and therefore can eliminate as a causative factor of poor performance.

Ensure that the reader in use is compatible with the communication protocols in use in your geographic locale (ie, forward and backward compatible).

Familiarize yourself with and follow the manufacturer's recommendations regarding reader care and scanning technique. When evaluating for the presence of a microchip, scanning should begin at the standardized site of microchip implantation in that species and geographic locale. If a microchip is not immediately identified, scanning should encompass a larger area and be done in slowly expanding concentric circles. Some manufacturers recommend a figure-eight pattern. Scanning should be done with the reader touching, or brushing, the animal's fur. Read distance can be slightly affected by the orientation of the microchip in relationship to the reader, and its impact will vary based on reader and microchip design. Fortunately, this rarely affects routine reader use. Although one cannot visualize the actual position of the implanted microchip relative to the reader during scanning, we can take advantage of this principle by slightly rocking the reader from side to side during the scanning process if the reader design allows.

To ensure that an implanted animal is identified, the scanning procedure should be done for a minimum of 10 seconds (longer if possible) and on two consecutive occasions before an animal is declared negative for the presence of a microchip. If possible, repeat the scanning process using a different reader. Fortunately this is rarely necessary, being the exception rather than the norm. As mentioned earlier, all recognized implantation sites should be scanned.

Battery charge is also important for portable, hand-held reader function. Ensure batteries are always fully charged and that the manufacturer's directions for battery care are followed closely.

Readers emit and receive electromagnetic energy and therefore can be affected by other electronic equipment or metallic objects. In this regard, shelters and veterinary clinics can be regarded as "hostile environments" due to the presence of computer terminals, fluorescent lights and stainless steel tables to mention a few. Try to maintain a distance of at least one meter (three feet) from electronic equipment. Ideally, one should not scan on stainless steel tables and remember to remove metal collars from the animal prior to scanning.

All implanted animals should be scanned annually to ensure proper function and location of the microchip.
Finally, all manufacturers and distributors provide support services for their products. Check the reader's performance frequently for read rate and range using a microchip that has not been implanted. Don't risk the use of a reader if its performance is in doubt. Instead, call the manufacturer or distributor for hardware support.

Microchip FAQs

  • How can one tell if the microchip being used is an ISO microchip or not, especially within the USA?
ISO 11784 and 11785 clearly define the bit content and communication protocol of microchips that adhere to these ISO standards. As such, a true ISO microchip has a 64 bit content resulting in a 15 digit numeric ID code of which the first 3 digits is the manufacturer's code that operates using FDX-B technology at a frequency of 134.2 kHz. In the USA, The current HomeAgain (Digital Angel) microchip is comprised of 48 bits resulting in a 10-alphanumeric ID number that does not contain Digital Angel's manufacturer's code and operates using FDX-A technology at a frequency of 125 kHz. This also applies to the AVID Eurochip. The AVID Friendchip also operates at 125 kHz and provides a 10 alphanumeric ID number but this number is encrypted, and hence requires a specially designed reader to be able to read. It is therefore also not a microchip that adheres to the ISO Standards 11784 or 11785. Both Digital Angel and AVID do manufacturer and distribute ISO standard microchips in markets outside of the USA.
  • What is the difference between the manufacturer and country codes and which is preferred?
The first three digits of the identification number stored in a microchip that meets ISO 11784/5 will be either a manufactures code or a country code.

Country Code
Microchips containing a number which starts with a country code can only be used in countries with a single central database which controls the issue of identification numbers. Each manufacturer selling product in such a country will ask the central database for a series of identification numbers. The manufacturer will then make microchips with these numbers each of which will start with the country code. These transponders will only be sold in the country represented by the three-digit code.
It is the responsibility of the central registry to be sure that no duplicate numbers are issued. A list of the codes for each county can be found at XXX

Manufacturers Code
In a country where there is no single central authority controlling the uniqueness of the code in each microchip, a manufacturer code is used. Each manufacturer applies to the International Committee on Animal Recording (ICAR) for a three-digit manufacturer code, which will start with 9. It is then the responsibility of each manufacturer to be sure that the number in each of the transponders that he makes is unique.

Technical details can be found in the ISO standards 11784 and 11785.

ICAR rules require that manufacturers abide by a code of conduct which includes the provisions outlined above. Manufacturers who do not abide by the code risk having their allocated manufacturer code withdrawn

  • What is Annex A and are microchips identified in Annex A truly ISO standard microchips?

When ISO standards 11784 and 11785 were developed, there was concern regarding protection of the installed base of microchips, often referred to as backward compatibility. ISO 11785 Annex A was developed to address this issue during the transition period between prior and ISO standard technology and defined the need for readers to read three technologies (Destron, Datamars, and Trovan) for a period of 2 years. AVID was not included in Annex A because they elected not to provide the encryption code with which to read their encrypted microchips. However, this 2-year period has long since passed and this was clearly defined in ISO 11785, Section 2 (Conformance), wherein it states "...transponders meeting the requirements of Annex A may be applied for a transition period of 2 years from the date of the first edition of this international standard." The date of the first edition was 1996, and as this time frame was completed in 1998, Annex A is no longer applicable, hence, Annex A microchips are not true ISO standard microchips.

More FAQs
Additional answers to commonly asked questions can be found in the links under the ISO and ICAR section of this webpage, specifically the articles titled "a brief history" and "all you wanted to know about microchips but were afraid to ask"

  • The American Veterinary Medical Association (AVMA) has an information page regarding 'Microchipping of Animals' on their website. Find out more here