Passive Transponder Tags

The system provides permanent, unique identification of each laboratory mouse through a subcutaneously implanted, passive transponder tag. Each tag stores a unique identification code that is read wirelessly by the LF Reader Modules, enabling automated, error-free tracking of individuals throughout a study. Implanting the tag in the animal is part of the system’s workflow (see Tag Implantation); for animal welfare and ethics requirements, see Animal Welfare and Ethics.

We do not supply Passive Transponder Tags or manufacture implantation syringes. Researchers obtain tags and syringes from a tag supplier. The tag specifications, biocompatibility, imaging compatibility and implantation guidance in this chapter are relayed from the suppliers’ documentation; the instructions supplied with the tag and syringe take precedence.

System Compatibility

Table: Tag compatibility requirements

Item	Specification
Supported protocol	ISO 11784/11785, FDX-B
Operating frequency	134.2 kHz
Modulation	FSK (Frequency Shift Keying)

The device works with any commercially available injectable glass tag that conforms to ISO 11784/11785, FDX-B at 134.2 kHz. This is the international standard used across the global veterinary and laboratory-animal identification industry.

Although the system is protocol-compatible with all compliant tags, we strongly recommend one of the following approaches:

1. Use one of the recommended tag models below;
2. Use tags from another supplier — please send a small number of samples (1 to 3 units) before your study begins. We will verify read performance, signal quality and full compatibility with the reader modules, and confirm the result, typically within 5 business days.

Recommended Tags

We recommend the following two tags, both confirmed compatible. The product information is compiled from the manufacturers’ and distributors’ public materials (as of 2026-10); their latest materials take precedence. Datasheets and biocompatibility documentation can be requested from the distributor at purchase and included with the ethics application where required.

All product names and trademarks belong to their respective owners. We have no affiliation or partnership with the companies below; our recommendation is based solely on read-compatibility testing.

Trovan ID162 FDX-B

• Manufacturer: Trovan
• Australian distributor: Microchips Australia (https://microchips.com.au/)
• Animal registry: Central Animal Records (CAR)
• Supply formats: all-in-one disposable implanter; or needle-only format for use with a reusable implanter
• Available sizes: Midi 1.4 × 8 mm; conventional 2 × 11.5 mm
• Recommended product: Trovan CAR All In One
• Product page (manufacturer): https://www.trovan.com/en/products/trovan-fdx-b
• Implantation guide (manufacturer): https://www.trovan.com/en/RFID-FAQ/animal-implantation-instructions
• Ordering page (Australian distributor): https://microchips.com.au/products/trovan-car-all-in-one

Caution

The Trovan Unique ID100 is not supported because it uses the FDX-A protocol. The system requires tags compliant with ISO 11784/11785, FDX-B at 134.2 kHz.

HID UC-1485 Global ISO FDX-B

• Manufacturer: HID Global
• Australian distributor: Oz Microchips (https://www.ozmicrochips.com.au/)
• Animal registry: Australasian Animal Registry (AAR)
• Available sizes: standard; Mini approximately 1.4 × 8 mm
• Supply format: all-in-one implanter, packs of 10

Caution

The UID MiniMax programmable microchip (model UC-1283) is not supported because it uses a proprietary communication protocol rather than the FDX-B protocol required by the system.

Biocompatibility

Injectable tags are generally hermetically sealed in medical-grade biocompatible glass. The glass is chemically inert and protects the internal electronics from body fluids; some models add a biocompatible coating such as Parylene C over the glass. Tags of this kind have long been used to identify pets and laboratory animals. For the encapsulation material and biocompatibility documentation of a given model, see the manufacturer links above or ask the distributor.

Imaging Compatibility

Table: Imaging compatibility of passive transponder tags

Modality	Notes
MRI	Glass tags can generally be used in MRI but produce a local artifact near the tag; the applicable field strengths and conditions are as stated in the supplier’s documentation for the chosen model
X-ray / CT	The tag is visible on imaging
Bioluminescence / fluorescence imaging	Dorsal subcutaneous placement does not obstruct ventral or lateral imaging fields

Note

Researchers performing MRI studies should evaluate whether the tag may produce localized susceptibility artifacts on their specific sequences within the region of interest. If this is a concern, the tag can be implanted at a site distant from the region of interest.

Implantation Guidance

The following relays the tag suppliers’ general guidance; the instructions supplied with the tag and syringe take precedence. For ethics and welfare requirements, see Animal Welfare and Ethics; all procedures must be performed in accordance with the protocol approved by your institution’s Animal Ethics Committee (AEC).

• Recommended implantation site: subcutaneous (SQ), dorsal midline, between the scapulae.
• Animal age: weaning age (≥ 3 weeks) or older. For younger mice, we recommend using a smaller tag (for example, the Trovan Midi or HID Mini sizes listed above).
• Anesthesia: we recommend performing all implantations under anesthesia. In practice, mice aged 3 weeks or older can generally also be implanted while awake and properly restrained without problems. Whether to use anesthesia, and the analgesia regimen, are decided by the researcher under the protocol approved by the institution’s AEC.
• Needle size: depends on the tag size; see the instructions supplied with the tag and syringe.

Tag suppliers generally provide single-use syringes pre-loaded with the tag. The entire process takes approximately 15 to 30 seconds, as follows:

1. Remove the sterile pre-loaded needle from its packaging and confirm the bevel is facing upward.
2. Restrain or anesthetize the mouse. Restraint can be facilitated with a commercial restrainer (e.g., a Plexiglass restraint tube or ScruffGuard) that allows grasping of the skin over the shoulders.
3. Wet the fur at the injection site with 70% ethanol to expose a sparsely haired area and minimize introduction of hair into the subcutaneous space.
4. Remove the needle guard to expose the needle.
5. Tent the skin over the inter-scapular region (between the shoulder blades).
6. In a smooth motion, insert the needle bevel up, parallel to the spine and directed toward the tail; the needle should be inserted at least 1 cm into the inter-scapular space.
7. Slowly depress the plunger to release the tag into the inter-scapular space; grasp the skin around the needle as it is withdrawn to prevent the tag from slipping out.
8. Withdraw the needle and discard it directly into a sharps container.
9. Pinch or flatten the skin closed at the injection site to prevent the tag from tracking out along the needle path, and continue to apply pressure for hemostasis.
10. If needed, close the entry point with tissue glue or a medical-grade cyanoacrylate adhesive (e.g., Surgi-Lock).
11. Remove the mouse from the restraint device and scan the tag with a compatible reader to confirm and record the identification code.

Post-implantation: no sutures or wound closure are required. Monitor the animal for 24 to 48 hours for any signs of swelling, infection or tag migration. Tag migration can occur when mice are very active, but it does not affect their health.