RFID Locates the Right Blood in Emergency Response


by Victor Vega

In life-threatening, emergency situations time is critical. Ensuring that the proper blood type is provided for a transfusion, quickly, is vital.

Each of thousands of blood bags within a blood bank are usually marked with human readable and bar code labels. Still, human errors unfortunately do occur. The process is especially tough under extreme time pressure and when layers of frost on frozen blood bags sometimes stop lasers from reading conventional bar codes.

In addition to blood type, other blood profile criteria may be necessary for delicate transfusions.  Extended phenotype, expiration dates, blood cross-match test details as well as ensuring extraction dates can be important.

Finding a specific hemo-derivative may be like finding a needle in a haystack. This becomes a serial process, reading one bag at a time, either visually or by scanning with a “line-of-sight” bar code reader.

With up to 80 blood bags within each case, finding the right bag can be a challenge, especially when personnel are working in a -35ºC chiller.

UHF RFID shows its maturity

Aqueous materials, such as water-based blood bags, imposed a challenge to UHF RFID until just a few years ago, when the only viable RFID solutions were the lower frequencies, HF or LF RFID. But generally speaking, the lower frequency consumable tag implementations are more costly and the read range too limited for applications like this.

For first responders trying to save lives, Ultra-High Frequency (UHF) RFID is a modern marvel. Until recently, UHF RFID capabilities had not been fully exploited. Their applications were initially targeting very broad inventory and supply chain visibility applications on non-aqueous materials.

Aifos Solutions, an Alien solutions partner based in Spain, has implemented a complete UHF tracking solution for the Blood and Tissue Bank of Balearic Islands (FBSTIB) to help improve upon safety and efficiency. They chose UHF tags because they were about a quarter the cost of HF tags.

Playing the fields, near and far

The short read ranges of LF and HF RFID are characteristic of their operating in what is called the “near field” or “magnetic field.” It is impractical for these lower frequencies to operate in what is known as the “far field” or “electric field.” UHF tags are much more simplistic in their construction (hence the lower cost) and they have the distinct advantage of being capable of operating in either or both the “near field” or the “far field” simultaneously.

In the UHF spectrum, far field developments were the first to be exploited, followed by near field UHF. Both offer significant contributions and clear advantages. Near field is predominately used in proximity to liquids and has a limited read range. In the UHF spectrum, read ranges are typically less than 12-18” with a tag just over a half-inch square.

When the far field component is used (a larger tag), UHF RFID read ranges can be quite extensive. A slight increase in tag size to 1” square can result in read ranges several feet in distance, and larger tags can easily read 10’s of feet away. The longer read range is particularly helpful for quick inventory management, or in the case of the blood bag application, it allows an entire case of 80 blood bags to be read as they pass through an entryway.

Dr. Josep Muncunill, MD and CEO of the blood bank, explains, “Maintaining inventory control, security and plasma quality accuracy has always been a challenge for blood banks. When we have thirty to forty thousand plasma bags in our inventory chamber and a medical emergency requires us to find the correct plasma bag as quickly as possible, the quality and speed of our data capture system is of the utmost importance.”

Another speedy application for RFID is that a reader can be set to mask a specific ID, operating like a Geiger counter. When a specific ID or blood type is needed the reader can scan through numerous blood bags, helping to pinpoint the “needle in the haystack” despite labels being obscured or covered with frost.

Additionally, silicon chips such as our Alien Technology Higgs-3 IC, which Aifos used, provide a unique identifier, known as the Unique Tag Identifier (UTID). A total of 96 bits of memory, above and beyond the conventional EPC memory, may be used for safety purposes, where a unique serialized factory programmed identifier insures all blood bags are uniquely identified. This additional memory offers extensive ancillary password protection for the data.

Personnel can now more accurately capture critical data and generate automated alerts when blood bags are removed from the freezer for prolonged periods, also ensuring proper cold chain management. With RFID solutions like these, inventory control, security, plasma quality accuracy, improved patient safety and increased efficiencies are elevated to a whole new level.

Ed. Note: Don’t let the title marketing director fool you. Guest columnist Victor Vega of Alien Technology is a go-to resource for engineering answers.  www.alientechnology.com