APIII - Advancing Practice, Instruction & Innovation Through Informatics

RFID Tag design for the Pathology Laboratory

Michael Riben, MD1 (mriben@mdanderson.org) , Mark J. Routbort, MD, PhD 2, ,and Gary
Andrechak 3 , Departments of 1Pathology and 2 Hematopathology, University of Texas MD Anderson Cancer Center, Houston, TX, and  3 Hitachi America, Ltd., Brisbane, CA

Context:  Long-term storage of tissue blocks and microscope slides represent a valuable asset archive for both patient care and research initiatives.  The manual tracking and coordination of asset lifecycle has hindered access to these assets. Recent advances in RFID (radio frequency identification) technology, with its potential for individual asset tagging, is a potentially positive disruptive technology.  One challenge to implementation involves identifying materials (tags and adhesive labels) that can survive the harsh environment of the histology and cytology laboratories.  A second challenge involves acquiring right-sized tags.

Technology:  Hitachi’s  passive RFID technology, called µ-chip (mu), offers very low-cost RFID tag manufacturing.  The µ-chip IC (integrated circuit) measures only 0.4mm square, about half the size of typical RFID ICs, while operating at 2.45GHz radio frequency (like Wi-Fi and Bluetooth), facilitating a smaller and simpler tag antenna.  This RFDI tag is composed of RFID electronic components (antenna and microchip) called inlets and is laminated within protective film materials.  It can easily fit the limited labeling space of a slide or block. 

Design:  Label film materials were tested against chemicals and stains used for histologic block processing,  and slide staining and cover-slipping.  Bare inlets and various label materials and adhesive types were applied to multiple types of glass slides.  Histology slides were stained using the Shandon Varistain® Gemini automated stainer.  Cytology slides were manually stained using Diff-Quik and Papinicolau staining methods.  Tags were applied to both the internal and external block cassettes and processed in a manner identical to tissue blocks.  RFID labels were evaluated for competent adhesiveness, stain absorption, and writability following staining.

Results:  Readability tests showed that inlets survived the rigors of block processing, slide staining and coverslipping.  After testing multiple adhesives and label film materials, the most promising film material is a commercially available high density gloss white biaxially oriented polypropylene material with an acrylic dispersion clear permanent adhesive.  This material offers stain absorption resilience and writability with common permanent markers. 

Conclusion:  The squared-design RFID tag from Hitachi America represents a viable antennae/chip combination which functionally meets distance/signal strength/durability requirements for laboratory workflow, while the design functionality meets the tight space constraints for application to the slides and blocks.  The high density polypropylene material adheres to the slide throughout the staining and cover-slipping process; and it does not absorb stain.  Next steps include process mapping and software customization to optimally map scanning "touch" points for assets throughout their production/storage lifecycle.