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Thoughts on use of RFID in Medication Management

By Dennis Tribble posted 01-04-2022 05:15


I have been working in automation for a little over 35 years now, and one thing I have long observed in our profession is a rapt interest in shiny new toys. Blockchain and RFID are two that come to mind. This is about RFID.

I first considered some RFID applications years ago when Mark Neuenschwander was running the UnSummit and asked me to comment about potential uses of RFID as an alternative to bar codes in Bar Code Medication Administration (BCMA). More on that in a moment, but in preparing for that presentation, I learned a few things about RFID:

  • The Wikipedia article on RFID seems reasonably complete. If you are not familiar with it, it might be worth a read. You will find information on what is summarized below in that article.
  • There are multiple RFID tag communication frequencies, and each has its limits. RFID scanners read only the RFID tags that match their frequency. So, a “universal” RFID tag for medication management would require standards.
  • Additionally, those various frequencies have different capabilities and limits, such as reading through glass, or water.
  • There are basically two types of RFID tags, passive and active
    • Passive RFID tags consist of a chip and an antenna; they are energized and activated when they come into the scan field of a reader, and “shout out” whatever they know. The price on these tags has come down remarkably in the last decade.
    • Active RFID tags consist of a chip, an antenna, and a battery, and constantly “shout out” everything they know. These tags tend to be expensive and are generally used for asset tracking. For this purpose, a network of scanners can triangulate on tags in an entire facility and identify where each of them is currently located.
  • Tags all have a “license plate” that is, for all intents and purposes, a globally unique identifier. Some tags have only this license plate.
  • Some tags are write-once-read-many-times (WORM); other tags can be written and read many times and can be updated with information. The latter tend to be active tags.
  • The data storage on a tag (active or passive) varies widely but, in general, the more data storage capacity a tag has, the more expensive it is.

The really attractive thing about RFID is that it does not require line-of-sight between the scanner and the tag, and, in some cases, requires no human action to perform a read, unlike bar codes which require that a user point a scanner at a particular bar code and pull a trigger to scan it.

Additionally, the RFID scanner projects a scanning field and reads every RFID tag it can find in that field.  Most scanners read between 30 and 60 passive tags per second.

  • Imagine a BCMA functionality wherein a caregiver could simply layout everything they planned to give to a patient, scan once and know almost immediately whether they had everything they needed and nothing they shouldn’t give! Imagine further that said scan could record the NDC, lot number and expiration date of everything that was scanned!
  • Imagine doing a count of inventory in a location by scanning it for a minute and getting a count of everything that is in that location.
  • Imagine inventory storage locations that kept a perpetual inventory by regularly scanning themselves for what they contain.
  • Imagine a delivery cart that could be tracked throughout its delivery trips so that it could be documented when it left the pharmacy, when it returned, and where it had been in between.
  • Imagine further that such a cart system could “know” when medications had been placed into it, and when those medications were removed from it.

These are also limitations of RFID; it takes some engineering to focus an RFID scan on a specific area so that it doesn’t read tags you did not want it to read. Unlike bar code scanning, that can be aimed at one item, it is far more difficult to “point” an RFID scanner at a single item and scan only that item.

Additionally, an RFID scanner cannot tell whether a package is full or empty. So, in the potential applications described previously, those inventories could be inaccurate if empty containers were replaced into those locations. Ideally, opening those containers would somehow destroy the RFID tag.

Whether or not the bar code contains other information, the actual identity of a medication in a medication bar code is the National Drug Code (NDC) which means that their use must be supported by a database that translates those NDCs into human-understandable medication descriptions. It does not seem likely that RFID would be any different, so RFID seems unlikely to avoid having to have such a database.

It remains to be seen how much information might be included in an RFID tag, and at what cost. GS1 has published an Electronic Product Code (EPC) standard that describes one implementation that would Global Trade Identification Number (in the US, this would contain the NDC) and various other information in a tag that appears to be gaining acceptance as a standard for consideration. This specification addresses a common 96-bit RFID tag; GS1 notes in their most recent EPC version that “In order to fit within 96 bits, some serial numbers have to be excluded” (see linked document, page 83). Given that the tag itself is serialized, an interesting question might be whether the manufacturer using such a tag would offer a crosswalk between the RFID tag and the serial number (where one exists).  

Perhaps the biggest issue regarding RFID tagging of medication items remains to be cost.

  • For all intents and purposes, bar coding is free. Prior to DSCSA requirements, NDC bar codes were part of the camera-ready art for pharmaceutical labels. There was an original investment in getting that art updated with the NDC bar code, but that was in 2006 (or earlier) and has long since been amortized.
  • To handle lot number, expiration date and (in some cases) serial number, that has had to change to having the bar code(s) printed during production; that is an infrastructure cost mandated by DSCSA and seems likely to occur whether or not RFID were adopted, so may not be an additional cost for this discussion. It is an interesting question how different the infrastructure cost might be for RFID.
  • In contrast, passive RFID tags cost in the range of 5 cents or more which means that, for a large portion of the medications we manage, it represents a significant overhead cost for medications that otherwise cost pennies.
  • Interestingly, it is my understanding that printing bar codes with lot-specific information on them requires that each bar code be scanned to ensure that it is readable. I have never seen data on the amount of waste that might produce in drug product production, but it would be an interesting number to know; RFID writing might avoid printer reliability problems associated with bar code printing.
  • I have not looked at the cost of changing out scanning equipment to support RFID scanning. I suspect that such scanners may be more expensive.

So, another interesting question might be whether the productivity gains from using an RFID tag would offset the additional cost for their deployment in terms of infrastructure and individual medication package cost.

One must also think about the impact of requiring pharmacy-based unit-dose packaging to become RFID enabled and how that might be done. It seems likely it would make the packaging more expensive. Would the packaging have to be larger to accommodate the tag and its antenna? Would the tag survive the heat-based sealing operation of a high-speed packager? Would the tag have to be applied after packaging? Or would pharmacy-based packaged items have to be handled with bar codes only and, if so, what impact would that have to user workflow?

While one can imagine certain usage scenarios where a limited number of RFID-tagged medications would be useful, it seems likely that broad-based use of RFID in place of bar coding would require that the vast majority of medication packages would be RFID tagged.

In my opinion, the road to that endpoint remains unclear. Until that path does become clear, I have difficulty seeing RFID replacing bar codes in medication management and am generally skeptical that a hybrid approach (bar codes and RFID) will be successful, except in niche applications. I would love to be proved wrong.

The use of active RFID to track delivery processes may be closer at hand. While the cost of active tags and the sensor network to track them can be additionally expensive, such networks already exist in some institutions to track assets such as infusion pumps and ventilators and, in a few instances, even people. In cases where that infrastructure is already in place, the additional cost to tag a delivery cart with a tag, and provision it within the asset tracking system might be quite reasonable and provide visibility to both the pharmacy and to caregivers who might be awaiting delivery where a particular medication was in its journey to its destination.

There can be no question that RFID technology is well-defined and in present use for at least some purposes, even in healthcare. Whether it will eventually reach the ubiquity necessary to replace bar codes in medication applications remains unclear, in my opinion.

What do you think?

As always, the opinions expressed in this blog are my own, and not necessarily those of ASHP or of my employer, BD.

Dennis A. Tribble, Pharm.D., FASHP

Ormond Beach, FL