Deciphering the meaning of RFID and RTLS


by John Swart | VP, Solutions | Infinite Leap

As Real-Time Technologies consultants, we are asked on a regular basis to help our healthcare clients decipher the meaning of, and comparison between, the technical terms “RFID” and “RTLS.”

The confusion between the two acronyms stems from the fact that a lot of people use the acronyms interchangeably. Especially if they are new to the topic. In this blog post, we’ll sort out both the true definitions and common usage of the two acronyms. But keep in mind that in every conversation about RFID or RTLS, people may be using the terms without the same definitional discipline that we’re using here. Therefore, you’ll always have to look for other clues in the conversation, or ask clarifying questions, if you need to be absolutely sure which technologies people are discussing.

In general, the term “Radio-Frequency ID” (RFID) means any use of radio signals to communicate the identity of a tag (and by database lookup, identify an object that is attached to the tag). By technical definition, there are two types of RFID:

● Passive RFID, where tags rely on RF energy transferred from a reader to the tag to power the tag.
● Active RFID, where tags contain a battery and therefore use their own power source to transmit an identification signal.

Since the passive tags are predominant in most industries, most folks who use the simple phrase “RFID” in their discussions are referring to the passive RFID technology. When they want to discuss the battery-powered tags, they generally use the more-precise terms “Active RFID” or “Active tags” to clarify their meaning. Again, not always, but generally.

If all your organization is trying to do is identify an asset (or the container of an asset) then all you need is “RFID.” (In this paragraph, I’m now using the phrase “RFID” the way it is used in common discussions, to mean “passive RFID”). The retail industry loves RFID, because they want to keep track of their inventory on the shelves, and they want to track that an item is a blue cardigan sweater, rather than a red pullover sweater. The manufacturing industry loves RFID because they can record exactly which boxes have passed a particular phase of the manufacturing process. These industries are generally more interested in inventory within a building than they are in hundreds of different named locations within a building. Passive RFID serves them well, and they generally just use the term “RFID” to describe their system.

But within healthcare applications, we are typically interested in both inventory and location. And we are interested in hundreds or thousands of locations (e.g., patient rooms, supply closets, soiled utility rooms) where the inventory (e.g., IV pumps) may be located. And we are also interested in knowing exactly where those very mobile IV pumps are located right now because we need to get them to patients. Therefore, for many healthcare use cases, we want a real-time locating system (RTLS) for our assets. The phrase “RTLS” therefore means the use of tags on assets that can tell a computer database (and thereby tell us) where all of the assets are residing right now, in real time. Not just telling us when it was last scanned at a portal, like a simple RFID system, but where it is right now exactly, by sending us location updates automatically and continuously. And also not just telling us that something is in our inventory, like a simple RFID system, but in what status it is exactly, e.g in use or dirty.

By functional definition, an RTLS is any system that gives us data about locations in real time. And there are several alternate technologies that can provide this type of data. And this is where things get really confusing, but let’s sort it out:
● One option for the technology for providing a real-time location data is passive RFID.
● But passive RFID is not the only way, nor the predominant way, that healthcare organizations build an RTLS. Most healthcare organizations use active RFID tags to build an RTLS. Those active RFID tags, with their batteries, can transmit reminders every few minutes about location and status of the asset.
● Therefore, every RTLS system uses some kind of RFID technology.
● But not all RFID technologies or designs can give you the real-time location and status information you want from an RTLS system.

Typically, the question that follows in this type of conversation is: “Which RTLS technology is the best?” The answer each time is pretty much the same: “It really just depends on what you are trying to accomplish”. (Would you have expected any other answer from a consultant who works with all of these technologies?)

Different RTLS technologies, such as Wi-Fi, BLE, infrared, ultrasound, passive RFID, and proprietary RF have different pros and cons, and different healthcare organizations have different issues they want to address (e.g. finding mobile equipment, understanding room utilization, or ensuring vaccines will not get spoiled). Each of these use cases require different accuracy levels of locating hardware, as well as different software functionality. Further, RTLS hardware technologies evolve over time, some at different rates than others, and they all dramatically differ when it comes to the Total Cost of Ownership (TCO). And finally, since many hospitals have many use cases, a hybrid package of solutions including both passive RFID and active-RTLS is often going to generate the best return on investment.

As you can see, there is a lot to keep track of when it comes to this type of technology. So, if you still need help with understanding the difference between RFID and RTLS, or if you would like to discuss the pros and cons between each of real-time technologies for your specific requirements – please give us a shout!

1 Response
  1. Another technology that enables RTLS is UWB (ultra-wideband) which is what my company’s RTLS (ENVisionIT) uses. It offers phenomenal accuracy within +/- 1 foot, doesn’t require a receiver/tag reader in every room to achieve this level of accuracy and has much greater reliability and stability than a wi-fi or infrared based system.