Some of you may remember the RFID tagged solid-phase reaction vessels and the associated reading and sorting devices that were marketed by IRORI in the late 1990's. That was the first commercial appearance of RFID in the laboratory market that I'm aware of, but it was short lived. Recently RFID has become much more visible in the commercial arena, with companies like Wal-Mart deciding to adopt the technology for tracking products. When they get involved with a technology, you know several things: 1) It's reliable; 2) It's inexpensive or it will become more inexpensive. So The LabMan thought it was time to take another look at RFID. To do so we talked to Rick Pestian, Senior Solutions Engineer from THE RFID Solutions Center, in Miamisburg Ohio.

Rick tells us that RFID is similar to bar-coding in that it's a technology that allows a unique identifier to be attached to an object. It's different from bar-coding in that the attached label or tag doesn't have to be visible to be read. The reading is accomplished via radio frequency broadcast of the unique identifier. The broadcast of the identifier is triggered by an RF pulse from a reading device, which is received by the RFID tag, which then responds by broadcasting its pre-programmed identifying information.

According to Rick, there are two basic types of RFID devices, active and passive. An active tag carries it's own power supply, whereas a passive tag depends upon an RF pulse from the reader to provide enough power to generate an ID broadcast. Active tags tend to be larger and more expensive, have a much longer read range and can store more information. Passive tags are much less expensive, smaller, have a much more limited read range and store less data. There are also two different frequency ranges used by RFID chips, High Frequency or HF (13.56 MHz) and Ultra High Frequency or UHF (915 MHz). All RFID chips must have an antenna to send and receive information, and it's the antenna size that tends to dictate the size of the entire RFID tag and has a great influence over it's read range. Longer antennae facilitate longer read ranges but increase the size of the overall package. HF devices can be smaller but have a much shorter read range, usually requiring the reading device to be within inches of the tag. UHF tags can usually be read at longer ranges. The price of RFID tags today ranges from 10 to 25 cents, depending on the exact technical specifications. Reader prices can range from several hundred dollars for simple, short-range devices to several thousand dollars for a longer-range device that also has more built-in capability, such as networking.

Where has RFID found success? Rick indicates that success has come primarily in the world of logistics and tracking of commercial packages, and in other cases where it's important to impart a very durable individual ID to a given container, document or even organism. The data capacity of RFID tags allows true individual ID's to be assigned across a vast population of tags, whereas the ability to do the same via bar coding is limited by label size. For instance, the pharmaceutical industry is now beginning to employ RFID to track individual product containers along the supply chain from manufacturing to market, to minimize the intrusion of counterfeit drugs and to provide higher assurance of product safety. Such a tag can contain not only an identifier, but also other information such as lot number or serial number, which can be useful in dealing with with quality deficiencies and resulting recall campaigns. The FDA is now mandating this type of "pedigree tracking".

Other uses? Tiny, subcutaneous RFID tags have been used for years to track and identify animals. If you have adopted a pet from a Humane Society animal shelter, chances are they have such a device implanted, which would allow them to be identified if found anywhere in the country. In October 2004, the FDA approved the first RFID chips that can be implanted in humans. The goal is better tracking of patients and patient data in hospitals. Naturally, this use has raised privacy concerns. The LabMan has participated in running events where each runner wore an RFID tag on their shoe, and individual times were recorded as the runners ran over scanning mats. Believe me, The LabMan does not run fast enough to need his time recorded to the hundredth of a second!

In the laboratory automation world, an obvious potential use for RFID technology is the identification and tracking of collections. One technical advantage is the ability to read multiple tags simultaneously, as one might want to do when taking an inventory. Rick indicates that under the right conditions, concurrent multi-tag reading, or "singulation" is possible for collections of 100's or perhaps even a 1000 tags, but not for numbers beyond that. The "right conditions" include a reasonably close read distance and lack of RF interference from metal, water or anything that can generate or distort electromagnetic energy. Motion of the tag or tagged item improves read rates and helps to overcome interferences. Since there tends to be a lot of both metal and liquids in the laboratory environment, Rick's advice is that one must test each potential application environment before jumping into the technology.

If you'd like to read more about the nitty-gritty details of RFID, Wikipedia has an excellent write-up on their site.

Until next time,

Domo Arigato, Mr. Roboto