For years, hospitals and other medical care facilities have deployed systems to track the location of critical assets as they moved throughout their buildings. These Real Time Location Systems (RTLS), typically use some sort of active RFID technology that includes a battery powered beacon. The beacon transmits its presence every few seconds and this signal is detected by multiple readers throughout the facility. The system then locates the asset’s position through triangulation.
These systems work well enough, but are riddled with several challenges:
- Most are accurate only to five feet or more. This is fine if the 5-foot radius is within one room. But if the item is close to a wall the system might report an item as being in the adjacent room. Thus, not providing an accurate accounting.
- Even if the beacon’s batteries last a few years, all of them will need to be replaced over time. This could be a massive endeavor, especially if a battery runs out before it is replaced. There would be no way of determining where the item is or if it’s even in the building.
- The reader infrastructure can be quite extensive. Triangulation requires all locations must be visible to three readers. Even in small facilities this can mean a large installation cost.
- Due to their battery and circuitry, active tags are relatively large and cannot be easily placed on many smaller assets.
- Active tags are expensive. Depending on the technology used, the beacons can run between $25 and $100. Making it hard to justify tagging anything but the most expensive assets.
Given these challenges, many hospitals have avoided moving forward with these solutions. But some new changes to an established technology are starting to revive interest in tracking solutions.
Passive RFID started becoming widely available about 20 years ago. It was adopted by the Department of Defense to track the movements of items on pallets and, more recently, has become popular with retailers to quickly inventory all items displayed on a store floor. Unlike active beacons, passive RFID tags do not have a battery that needs to be replaced. Instead, they are activated when they come in range of a reader. As such they are small (some are the size of a paper label) and inexpensive (as low as 25 cents). This allows them to be affixed to almost any asset.
The downside has always been distance. Without a power source of their own, passive tags typically max out at 20 feet or so – too short to triangulate in large spaces. Instead, readers are installed at key “choke points” where items pass by. The more readers installed, the more detailed the picture. But new advances in chip and antenna designs have greatly improved their read range and performance. Multiplexed reader antennas provide greater flexibility in coverage and cost per read point. And new, software-controlled, phased array antennas can detect direction of motion (whether an item is going in or out of a room), a key attribute in determining an item’s location. These improvements have started to make passive RFID systems more attractive.
As more healthcare facilities have systems installed, there has been a re-thinking of what is required from an RTLS system:
- Do I really need real-time visibility? Do I have to see an item rolling down the hallway or do I just care where it ends up?
- How much detail do I need? Do I care where in a room an item is? Or is just knowing it is in the room sufficient?
- What items really need to be tracked? Yes, infusion pumps and defibrillators are vital. But what does it cost when a patient cannot be discharged on time because a wheelchair can’t be located? And can I justify attaching a $75 active beacon to each item?
More and more, attitudes are changing as the various technologies grow and evolve.
If you are considering installing an RTLS system, consider the following action plan:
- Make a list of all of the items you believe are important enough to track.
- Determine how often you need to ascertain their locations.
- Determine where these items typically are located and where they move.
- Calculate the existing costs of losing and locating these assets.
- Compare the tag and infrastructure costs of various solutions.
- Determine the optimal solution for your situation.
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